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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-06-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000799166</issuerCik>
        <issuerName>MASSBANK CORP</issuerName>
        <issuerTradingSymbol>MASB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001134600</rptOwnerCik>
            <rptOwnerName>BRANDI GERARD H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MASSBANK CORP</rptOwnerStreet1>
            <rptOwnerStreet2>123 HAVEN STREET</rptOwnerStreet2>
            <rptOwnerCity>READING</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01867</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, Chairman &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-06-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>133.999</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.78</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>241374.2012</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares in one custodian account sold by Mr. Brandi on behalf of the beneficiary, who is no longer a minor.</footnote>
        <footnote id="F2">Includes 28,908.0142 shares owned indirectly by Gerard H. Brandi under the MASSBANK Employee Stock Ownership Plan (ESOP).</footnote>
        <footnote id="F3">Also includes 18,837.528 shares of common stock of MASSBANK Corp. stock owned by Mr. Brandi's spouse, to which Mr. Brandi disclaims beneficial ownership. This report shall not be deemed an admission that Mr. Brandi is the beneficial owner of these shares. This share position includes the following shares acquired during 2007 pursuant to the reinvestment of dividends under the MASSBANK Corp Dividend Reinvestment Plan: 135.107sh @$33.2933 per sh on 02/16/07; 137.538sh @$32.98 on 05/18/07.</footnote>
        <footnote id="F4">Also includes 1,360.928 shares of common stock of MASSBANK Corp. stock owned indirectly by Mr. Brandi as custodian for minors. This share position includes the following shares acquired during 2007 pursuant to the reinvestment of dividends under the MASSBANK Corp Dividend Reinvestment Plan: 8.020sh
@$33.2933 per sh on 02/16/07; and 8.165sh @$32.98 on 05/18/07.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Gerard H. Brandi</signatureName>
        <signatureDate>2007-06-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
