<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>5/A</documentType>

    <periodOfReport>2004-10-18</periodOfReport>

    <dateOfOriginalSubmission>2005-05-13</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000720671</issuerCik>
        <issuerName>HALIFAX CORP</issuerName>
        <issuerTradingSymbol>HX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001198709</rptOwnerCik>
            <rptOwnerName>SCURLOCK ARCH C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>1994-01-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>17505</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.5</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17505</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2004-10-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>W</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>65493</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>82998</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY ARCH C. SCURLOCK CHILDREN'S TRUST</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>7% HALIFAX CONVERTIBLE DEBENTURE DUE 07/01/2007</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.19</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-10-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>W</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10449</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-10-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2007-07-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>HALIFAX COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10449</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10449</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY ARCH C. SCURLOCK CHILDREN'S TRUST</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">THE REPORTING PERSON IS REPORTING THE AMOUNT OF THE COMMON STOCK AND THE NUMBER OF SHARES PROPORTIONATE TO THE REPORTING PERSON'S INTEREST IN THE ARCH C. SCURLOCK CHILDREN'S TRUST.  THE REPORTING PERSON DISCLAIMS BENEFICIAL OWNERSHIP OF THESE SECURITIES, AND THIS REPORT SHALL NOT BE DEEMED AN ADMISSION THAT THE REPORTING PERSON IS THE BENEFICIAL OWNER OF SUCH SECURITIES FOR PURPOSES OF SECTION 16 OR FOR ANY OTHER PURPOSE.</footnote>
        <footnote id="F2">THE DEBENTURE WAS PAID OFF IN JULY 2005.  THEREFORE, IT IS NO LONGER CONVERTIBLE INTO SHARES OF COMMON STOCK.</footnote>
        <footnote id="F3">THE REPORTING PERSON IS REPORTING THE AMOUNT OF THE CONVERTIBLE NOTE AND THE NUMBER OF SHARES PROPORTIONATE TO THE REPORTING PERSON'S INTEREST IN THE ARCH C. SCURLOCK CHILDREN'S TRUST.  THE REPORTING PERSON DISCLAIMS BENEFICIAL OWNERSHIP OF THESE SECURITIES, AND THIS REPORT SHALL NOT BE DEEMED AN ADMISSION THAT THE REPORTING PERSON IS THE BENEFICIAL OWNER OF SUCH SECURITIES FOR PURPOSES OF SECTION 16 OR FOR ANY OTHER PURPOSE.  VALUE OF SUBORDINATED DEBT ATTRIBUTABLE TO REPORTING PERSON WAS $33,333.</footnote>
        <footnote id="F4">N/A</footnote>
    </footnotes>

    <remarks>THIS FORM 5 IS BEING AMENDED TO CORRECT THE NUMBER OF SHARES THE DEBENTURE WAS CONVERTIBLE INTO AS WELL AS THE CONVERSION PRICE, WHICH WAS INADVERTENLY INCORRECT ON THE ORIGINAL FORM.</remarks>

    <ownerSignature>
        <signatureName>ARCH C. SCURLOCK JR.</signatureName>
        <signatureDate>2005-08-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
