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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-11-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001001902</issuerCik>
        <issuerName>INTEVAC INC</issuerName>
        <issuerTradingSymbol>IVAC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001574629</rptOwnerCik>
            <rptOwnerName>Vardeman Ryan L.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8333 DOUGLAS AVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 775</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75225</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Intevac Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-11-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Intevac Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1053924</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.55</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2024-11-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10300</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-11-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Intevac Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10300</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10300</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These are restricted stock units awarded to the Reporting Person and each restricted stock unit represents a contingent right to receive one share of IVAC common stock. The restricted stock units will vest on 5/15/2025.</footnote>
        <footnote id="F2">This statement is filed by and on behalf of Ryan L. Vardeman. Palogic Value Fund, L.P., a Delaware limited partnership (Palogic Value Fund), is the record and direct beneficial owner of the securities covered by this statement. Palogic Value Management, L.P., a Delaware limited partnership (Palogic Value Management), is the  general partner of, and may be deemed to beneficially own securities owned by, Palogic Value Fund. Palogic Capital Management, LLC, a Delaware limited liability company (Palogic Capital Management), is the general partner of, and may be deemed to beneficially own securities beneficially owned by, Palogic Value Management. Mr. Vardeman is the sole member of, and may be deemed to beneficially own securities beneficially owned by, Palogic Capital Management. Mr. Vardeman is also a limited partner in, and may be deemed to beneficially own securities owned by, Palogic Value Fund.</footnote>
        <footnote id="F3">The reporting person states that neither the filing of this statement nor anything herein shall be deemed an admission that the reporting person is, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended or otherwise, the beneficial owner of any securities covered by this statement. The reporting person disclaims beneficial ownership of the securities covered by this statement, except to the extent of the pecuniary interest of the reporting person in such securities. The reporting person may be deemed to be a member of a group with respect to the issuer or securities of the issuer for purposes of Section 13(d) or 13(g) of the Securities Exchange Act of 1934.</footnote>
        <footnote id="F4">The reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such persons are, for the purposes of Section 13(d) or 13(g) of the Securities Exchange Act of 1934 or any other purpose, a member of a group with respect to the issuer or securities of the issuer.</footnote>
        <footnote id="F5">This option shall be exercisable, in whole or in part on May 15, 2025.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Ryan L. Vardeman</signatureName>
        <signatureDate>2024-11-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
