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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 /omIbzqmLlf9a6aOgVkeEg==

<SEC-DOCUMENT>0001302018-10-000007.txt : 20100603
<SEC-HEADER>0001302018-10-000007.hdr.sgml : 20100603
<ACCEPTANCE-DATETIME>20100603123140
ACCESSION NUMBER:		0001302018-10-000007
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100601
FILED AS OF DATE:		20100603
DATE AS OF CHANGE:		20100603

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PERCEPTRON INC/MI
		CENTRAL INDEX KEY:			0000887226
		STANDARD INDUSTRIAL CLASSIFICATION:	OPTICAL INSTRUMENTS & LENSES [3827]
		IRS NUMBER:				382381442
		STATE OF INCORPORATION:			MI
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		47827 HALYARD DRIVE
		CITY:			PLYMOUTH
		STATE:			MI
		ZIP:			48170-2461
		BUSINESS PHONE:		3134144816

	MAIL ADDRESS:	
		STREET 1:		47827 HALYARD DRIVE
		CITY:			PLYMOUTH
		STATE:			MI
		ZIP:			48170-2461

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DECOCCO PHILIP J
		CENTRAL INDEX KEY:			0001256018

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-20206
		FILM NUMBER:		10875083

	MAIL ADDRESS:	
		STREET 1:		47827 HALYARD DRIVE
		CITY:			PLYMOUTH
		STATE:			MI
		ZIP:			48071
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000887226</issuerCik>
        <issuerName>PERCEPTRON INC/MI</issuerName>
        <issuerTradingSymbol>PRCP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001256018</rptOwnerCik>
            <rptOwnerName>DECOCCO PHILIP J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>47827 HALYARD DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PLYMOUTH</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-06-01</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1875</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>57678</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On June 1, 2010, the reporting person received 1,875 shares in lieu of his Board Compensation pursuant to the Directors Stock Purchase Rights under the 2004 Stock Incentive Plan, an exempt plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Sylvia M Smith on behalf of Philip J DeCocco</signatureName>
        <signatureDate>2010-06-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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