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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-07-19</periodOfReport>

    <issuer>
        <issuerCik>0000730255</issuerCik>
        <issuerName>CALIFORNIA AMPLIFIER INC</issuerName>
        <issuerTradingSymbol>CAMP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001190071</rptOwnerCik>
            <rptOwnerName>GOLD RICHARD B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CALIFORNIA AMPLIFIER, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1401 N. RICE AVENUE</rptOwnerStreet2>
            <rptOwnerCity>OXNARD,</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>93030</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>2004-07-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Richard K. Vitelle, Attorney In Fact</signatureName>
        <signatureDate>2004-07-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2004-07-19
0000730255
CALIFORNIA AMPLIFIER INC
CAMP
0001190071
GOLD RICHARD B
C/O CALIFORNIA AMPLIFIER, INC.
1401 N. RICE AVENUE
OXNARD,
CA
93030
1
0
0
0
Common Stock
2004-07-19
4
P
0
4000
6.50
A
4000
D
Richard K. Vitelle, Attorney In Fact
2004-07-20