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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2023-05-12</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000042888</issuerCik>
        <issuerName>GRACO INC</issuerName>
        <issuerTradingSymbol>GGG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001976841</rptOwnerCik>
            <rptOwnerName>Anfang Heather L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>88 11TH AVENUE NE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MINNEAPOLIS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55413</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/ Shannon E. Quirk, attorney-in-fact for Ms. Anfang</signatureName>
        <signatureDate>2023-05-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
