<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-07-24</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>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </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><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>11542</value></transactionShares><transactionValue><value>14.1066</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>15542</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>6607</value></transactionShares><transactionValue><value>10.5866</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>22149</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>18149</value></transactionShares><transactionValue><value>26.7941</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value><footnoteId id="F1"/><footnoteId id="F2"/></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>14.1066</value></conversionOrExercisePrice><transactionDate><value>2003-07-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>11542</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1997-07-10</value></exerciseDate><expirationDate><value>2006-07-10</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>11542</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Employee stock option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>10.5866</value></conversionOrExercisePrice><transactionDate><value>2003-07-24</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>6607</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1999-10-05</value></exerciseDate><expirationDate><value>2008-10-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>6607</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value><footnoteId id="F3"/></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">3,000 shares are held by Company to implement restrictions on transfer unless and until certain conditions are met.</footnote><footnote id="F2">Reporting person also indirectly owns 1,549.6180 shares as 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 07/18/03.</footnote><footnote id="F3">Reporting person also (i) indirectly owns 995.0521 share equivalents, payable in cash upon retirement or after termination of employment, represented by Company stock fund units credited under the Company's Nonqualified Savings Plan based on information furnished by the Plan Administrator as of 07/18/03; share equivalents may not equal the number of share equivalents represented by a prior balance plus additions due to variances in the proportion of unvested cash held in the reference fund used to determine unit values of the Company stock fund under the Plan, and (ii) directly owns options to purchase a total of 142,064 shares at exercise prices ranging from $10.5866 - $20.3490 and vesting dates ranging from currently exercisable to 10/7/2005.</footnote></footnotes><ownerSignature><signatureName>James P. O'Shaughnessy</signatureName><signatureDate>2003-07-25</signatureDate></ownerSignature></ownershipDocument>

