PURPOSE: To eliminate the sense of discomfort of a user and also to obtain a fingerprint image having high quality needed for a fingerprint collation processing by performing the image collecting timing control after the detection of a fact that an object to be checked has been set on its mounting surface and at the same time giving a restamping request to a user in a short time.

CONSTITUTION: When a user places his finger on the transparent mounting surface of a fingerprint input part 9, the part 9 applies the photoelectric conversion to a fingerprint image and stores the obtained fingerprint swelling line pattern in an image memory 12 via an image collecting timing control part 10 and a pseudo fingerprint input deciding part 11. Meanwhile a personal ID number is inputted to a collation processor 15 through a keyboard 14. Thus the processor 15 makes an access to a register file 13 based on the inputted ID number and calls the fingerprint feature information corresponding to the ID number out of the fingerprint feature information on the user stored previously in the file 13. Then the processor 15 compares the fingerprint feature information called out of the file 13 with the fingerprint swelling line pattern stored in the memory 12 to check the identity of them.