<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-08-29</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000737758</issuerCik>
        <issuerName>TORO CO</issuerName>
        <issuerTradingSymbol>ttc</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001167150</rptOwnerCik>
            <rptOwnerName>MCINTYRE J LAWRENCE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8111 LYNDALE AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGDALE</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55420-1196</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President, Secy. &amp; G.C.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-08-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>46.98</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>980.353</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">In addition, reporting person owns directly 10,216.174 Common Stock Units, 5,108.071 Matching Units and 27,918.304 Performance Share Units in The Toro Company Deferred Compensation Plan for Officers and 10,144.405 shares indirectly in The Toro Company Investment, Savings and ESOP.</footnote>
        <footnote id="F2">Reporting person sold 10,000 shares to the Company in a private transaction.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>N. Jeanne Ryan</signatureName>
        <signatureDate>2003-09-03</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2003-08-29
0
0000737758
TORO CO
ttc
0001167150
MCINTYRE J LAWRENCE
8111 LYNDALE AVENUE SOUTH
BLOOMINGDALE
MN
55420-1196
0
1
0
0
Vice President, Secy. & G.C.
Common Stock
2003-08-29
4
S
0
10000
46.98
D
980.353
D
In addition, reporting person owns directly 10,216.174 Common Stock Units, 5,108.071 Matching Units and 27,918.304 Performance Share Units in The Toro Company Deferred Compensation Plan for Officers and 10,144.405 shares indirectly in The Toro Company Investment, Savings and ESOP.
Reporting person sold 10,000 shares to the Company in a private transaction.
N. Jeanne Ryan
2003-09-03