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

    <documentType>4/A</documentType><periodOfReport>2003-12-15</periodOfReport><dateOfOriginalSubmission>2003-12-16</dateOfOriginalSubmission>
    <issuer>
        <issuerCik>0000072331</issuerCik>
        <issuerName>NORDSON CORP</issuerName>
        <issuerTradingSymbol>NDSN</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001061821</rptOwnerCik>
            <rptOwnerName>GACKA MARK G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>28601 CLEMENS ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WESTLAKE</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44145</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>VICE PRESIDENT</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>COMMON SHARES</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>35268</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><footnotes><footnote id="F1">Includes 14,399 shares owned thru Co. 401(k) Plan.  Reporting person previously reported 14,410 shares owned thru Co. 401(k) Plan -- no longer reinvesting dividends as previously reported in Co. 401(k) Plan.  Also includes 235 shares owend thru co. Excess Retirement Plan.</footnote></footnotes><remarks/><ownerSignature><signatureName>Robert E. Veillette, Attorney-In-Fact</signatureName><signatureDate>2004-01-13</signatureDate></ownerSignature></ownershipDocument>

