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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-01-19</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001167141</rptOwnerCik>
            <rptOwnerName>MELROSE KENDRICK B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8111 LYNDALE AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGTON</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55420-1196</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman of the Board</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-01-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>348740</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.83</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>843121</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1832</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By grandchildren</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>38115.9007</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>The Toro Company Investment, Savings &amp; ESOP</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On January 23, 2006, Toro distributed to Mr. Melrose 845,431 shares of Common Stock previously held as Common Stock units for his benefit under The Toro Company Deferred Compensation Plan for Officers.  Toro also withheld from distribution 348,740 shares to pay income and related taxes required by law.  The Common Stock units represented compensatin earned, but deferred, by Mr. Melrose under The Toro Company Performance Share Plan and The Toro Company Annual Management Incentive Plan II from 1999 through 2005.  The distribution was made pursuant to Mr. Melrose's prior deferral election to take a lump sum distribution following his December 31, 2005 retirement as an employee of Toro.  Under the terms of the plan, such a distribution is to be on or about January 15 following termination, and in Mr. Melrose's case, was ordered on January 19, 2006.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>N. Jeanne Ryan, Atty-In-Fact</signatureName>
        <signatureDate>2006-01-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-01-19
0000737758
TORO CO
TTC
0001167141
MELROSE KENDRICK B
8111 LYNDALE AVENUE SOUTH
BLOOMINGTON
MN
55420-1196
1
1
0
0
Chairman of the Board
Common Stock
2006-01-19
4
F
0
348740
44.83
D
843121
D
Common Stock
1832
I
By grandchildren
Common Stock
38115.9007
I
The Toro Company Investment, Savings & ESOP
On January 23, 2006, Toro distributed to Mr. Melrose 845,431 shares of Common Stock previously held as Common Stock units for his benefit under The Toro Company Deferred Compensation Plan for Officers.  Toro also withheld from distribution 348,740 shares to pay income and related taxes required by law.  The Common Stock units represented compensatin earned, but deferred, by Mr. Melrose under The Toro Company Performance Share Plan and The Toro Company Annual Management Incentive Plan II from 1999 through 2005.  The distribution was made pursuant to Mr. Melrose's prior deferral election to take a lump sum distribution following his December 31, 2005 retirement as an employee of Toro.  Under the terms of the plan, such a distribution is to be on or about January 15 following termination, and in Mr. Melrose's case, was ordered on January 19, 2006.
N. Jeanne Ryan, Atty-In-Fact
2006-01-23