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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-06-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000096536</issuerCik>
        <issuerName>TAYLOR DEVICES INC</issuerName>
        <issuerTradingSymbol>TAYD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001230499</rptOwnerCik>
            <rptOwnerName>HILL RICHARD G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>90 TAYLOR DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 748</rptOwnerStreet2>
            <rptOwnerCity>NORTH TONAWANDA</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>14120-0748</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.655</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>63412</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Distribution of shares of issuer as merger consideration in connection with the Agreement and Plan of Merger dated as of November 30, 2007 by and between the issuer and Tayco Developments, Inc.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Richard G. Hill</signatureName>
        <signatureDate>2008-06-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2008-06-05
0
0000096536
TAYLOR DEVICES INC
TAYD
0001230499
HILL RICHARD G
90 TAYLOR DRIVE
PO BOX 748
NORTH TONAWANDA
NY
14120-0748
1
1
0
0
Vice President
Common Stock
2008-06-05
4
J
0
4800
6.655
A
63412
D
Distribution of shares of issuer as merger consideration in connection with the Agreement and Plan of Merger dated as of November 30, 2007 by and between the issuer and Tayco Developments, Inc.
/s/Richard G. Hill
2008-06-09