<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-11-13</periodOfReport>
    <issuer>
        <issuerCik>0001024478</issuerCik>
        <issuerName>ROCKWELL  AUTOMATION INC</issuerName>
        <issuerTradingSymbol>ROK</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204913</rptOwnerCik>
            <rptOwnerName>O SHAUGHNESSY JAMES P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>777 EAST WISCONSIN AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1400</rptOwnerStreet2>
            <rptOwnerCity>MILWAUKEE</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>53202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle> V. Pres. and Chief I P Coun.</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-11-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>3300</value></transactionShares><transactionPricePerShare><value>11.6038</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>7300</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1565.8734</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value><footnoteId id="F1"/></directOrIndirectOwnership><natureOfOwnership><value>By Savings Plan</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>17.3914</value></conversionOrExercisePrice><exerciseDate><value>1997-12-09</value></exerciseDate><expirationDate><value>2006-12-09</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>13690</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>13690</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>16.278</value></conversionOrExercisePrice><exerciseDate><value>1998-07-02</value></exerciseDate><expirationDate><value>2007-07-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>11409</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>11409</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>15.527</value></conversionOrExercisePrice><exerciseDate><value>1998-12-03</value></exerciseDate><expirationDate><value>2007-12-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>10000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>10000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>10.5866</value></conversionOrExercisePrice><exerciseDate><value>1999-10-05</value></exerciseDate><expirationDate><value>2008-10-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>12215</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>12215</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>20.349</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><value>2009-10-04</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>18750</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>18750</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeTransaction><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>11.6038</value></conversionOrExercisePrice><transactionDate><value>2003-11-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>3300</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2001-10-02</value></exerciseDate><expirationDate><value>2010-10-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>3300</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>17700</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>13.40</value></conversionOrExercisePrice><exerciseDate><value>2002-10-01</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2011-10-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>27500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>27500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>15.50</value></conversionOrExercisePrice><exerciseDate><value>2003-10-07</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2012-10-07</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>27500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>27500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>27.75</value></conversionOrExercisePrice><exerciseDate><value>2004-10-06</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2013-10-06</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>27500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>27500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Common Stock Share Equivalents</value></securityTitle><conversionOrExercisePrice><footnoteId id="F4"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1074.2145</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1074.2145</value><footnoteId id="F4"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>Nonqual. Savings Plan</value></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Shares represented by Company stock fund units under the Company's Savings Plan which were acquired on a periodic basis pursuant to the Plan, based on information furnished by the Plan Administrator as of 10/31/2003.</footnote><footnote id="F2">12,500 shares are currently exercisable and 6,250 shares become exercisable on the date on which the closing price of the shares on the New York Stock Exchange-Composite Transactions shall have exceeded 150% of the Fair Market Value on 10/04/1999, for at least 20 consecutive trading days, or, if earlier, on 10/04/2006.</footnote><footnote id="F3">The option vests in three substantially equal annual installments beginning on the date exercisable.</footnote><footnote id="F4">Share equivalents represented by Company stock fund units credited under the Company's nonqualified savings plan based on information furnished by the Plan Administrator as of 10/31/2003.  The number of share equivalents represented by the balance of a participant's Company stock fund account may not exactly equal the number of share equivalents represented by a prior balance plus additions due to variances in the proportion of uninvested cash held in the reference fund used to determine unit values of the Company stock fund under the plan. </footnote><footnote id="F5">The share equivalents are payable in cash upon retirement or after termination of employment.</footnote></footnotes><remarks/><ownerSignature><signatureName>K. A. Balistreri, Attorney-in-fact for James P. O'Shaughnessy</signatureName><signatureDate>2003-11-13</signatureDate></ownerSignature></ownershipDocument>

