<?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>0001229487</rptOwnerCik>
            <rptOwnerName>TAYLOR DOUGLAS P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>90 TAYLOR DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></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>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>61800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.655</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85421</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/Douglas P. Taylor</signatureName>
        <signatureDate>2008-06-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2008-06-05
0
0000096536
TAYLOR DEVICES INC
TAYD
0001229487
TAYLOR DOUGLAS P
90 TAYLOR DRIVE
NORTH TONAWANDA
NY
14120-0748
1
1
0
0
President
Common Stock
2008-06-05
4
J
0
61800
6.655
A
85421
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/Douglas P. Taylor
2008-06-09