<?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>0001167142</rptOwnerCik>
            <rptOwnerName>MEYER KAREN M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TORO CO</rptOwnerStreet1>
            <rptOwnerStreet2>8111 LYNDALE AVE SOUTH</rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGTON</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55420</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>vice president administration</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>6000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>46.98</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>880</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">reporting person sold 6,000 shares to the Company in a private transaction.</footnote>
        <footnote id="F2">In addition, the reporting person owns direct 11,086.561 Common Stock Units, 5,543.194 Matching Units and 47,599.154 Performance Share Units in The Toro Company Performance Share Plan and 19,607.128 shares indirectly in The Toro Company Investment, Savings &amp; ESOP.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>N. Jeanne Ryan, Power of Attorney</signatureName>
        <signatureDate>2003-09-03</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2003-08-29
0
0000737758
TORO CO
ttc
0001167142
MEYER KAREN M
TORO CO
8111 LYNDALE AVE SOUTH
BLOOMINGTON
MN
55420
0
1
0
0
vice president administration
common stock
2003-08-29
4
S
0
6000
46.98
D
880
D
reporting person sold 6,000 shares to the Company in a private transaction.
In addition, the reporting person owns direct 11,086.561 Common Stock Units, 5,543.194 Matching Units and 47,599.154 Performance Share Units in The Toro Company Performance Share Plan and 19,607.128 shares indirectly in The Toro Company Investment, Savings & ESOP.
N. Jeanne Ryan, Power of Attorney
2003-09-03