To perform the collation of images such as fingerprints, etc., in a simple constitution by storing the data on a linear image that is segmented from a 1st image in a prescribed storage means and comparing the image data stored in the storage means with the data on a 2nd image to judge the coincidence or non-coincidence between both data.

When a user inputs a request for collation of fingerprints, the fingerprint data D2 on a checking object is fetched via a fingerprint data input part 4 and then temporarily stored in a checking fingerprint memory 6. Then the data temporarily held in a tested fingerprint memory 6 D2 and the corresponding fingerprint data D1 registered in a fingerprint data base 5 are inputted to a collation rate detection part 7 in response to the user operation that is inputted via a key input part 2. The degree of coincidence is detected between both data D1 and D2. A system control circuit 3 decides the coincidence of fingerprints based on the detected degree of coincidence and notifies the user of a message via a display part 8.