<SUBMISSION>
<ACCESSION-NUMBER>0001144692-11-000001
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20101231
<FILING-DATE>20110104
<DATE-OF-FILING-DATE-CHANGE>20110104
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BRONSON STEVEN N
<CIK>0001000383
<STATE-OF-INCORPORATION>FL
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-30083
<FILM-NUMBER>11505927
</FILING-VALUES>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>QUALSTAR CORP
<CIK>0000758938
<ASSIGNED-SIC>3695
<IRS-NUMBER>953927330
<STATE-OF-INCORPORATION>CA
<FISCAL-YEAR-END>0630
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3990-B HERITAGE OAK COURT
<CITY>SIMI VALLEY
<STATE>CA
<ZIP>93063
<PHONE>805-583-7744
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3990-B HERITAGE OAK COURT
<CITY>SIMI VALLEY
<STATE>CA
<ZIP>93063
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BKF CAPITAL GROUP INC
<CIK>0000009235
<ASSIGNED-SIC>6282
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-30083
<FILM-NUMBER>11505928
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>ONE ROCKEFELLER PLAZA
<CITY>NEW YORK
<STATE>NY
<ZIP>10020
<PHONE>2123328400
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE ROCKEFELLER PLAZA
<CITY>NEW YORK
<STATE>NY
<ZIP>10020
</MAIL-ADDRESS>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>BAKER FENTRESS & CO
<DATE-CHANGED>19970829
</FORMER-NAME>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>BAKER FENTRESS & CO ET AL
<DATE-CHANGED>19940714
</FORMER-NAME>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000758938</issuerCik>
        <issuerName>QUALSTAR CORP</issuerName>
        <issuerTradingSymbol>QBAK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000009235</rptOwnerCik>
            <rptOwnerName>BKF CAPITAL GROUP INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>225 N.E. MIZNER BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>BOCA RATON</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33432</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001000383</rptOwnerCik>
            <rptOwnerName>BRONSON STEVEN N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5700</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1563400</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares were purchased by BKF Captial Group, Inc, in an open market transaction.</footnote>
        <footnote id="F2">BKF Captial Group, Inc. owns of record 1,505,700 shares of Qualstar Corporation's common stock.  Steven N. Bronson, as the Chairman and President of BKF Captial Group, Inc. may be deemed to beneficially own the shares of Qualstar Corporation held by BKF Captial Group, Inc.  Mr. Bronson, as the sole owner of BA Value Investors, LLC, is the beneficial owner of 57,700 shares of Qualstar Corporation.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Steven N. Bronson, President</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Steven N. Bronson</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
