PURPOSE: To always clean up a finger depressing face by sliding a protection cover formed on the finger depressing face of a transparent body and sweeping dirt stuck to the finger depressing face with cleaning cloth prepared on the rear face of the protection cover.

CONSTITUTION: The transparent body 2 is usually covered with the protection cover 1, and at the time of impressing a finger print, the cover 1 is slided with a finger 3 in an arrow F direction and the finger 3 is depressed to the finger depressing face of the exposed transparent body 2. The finger depressing face cleaning cloth 4 is fitted to the lower side of the cover 1 and a cleaning solution 6 in a tank 5 is supplied to the cloth 4 through sponge 7 every opening of the cover 1. A tank cover 8 is arranged on the lower part of the cover 1, and at the time of closing the cover 1, the cover 8 closes the tank 5 to prevent the cleaning solution 6 from being evaporated. A spring guide 10 is fitted to the cover 1 through a member 9 and the guide 10 is energized with a spring 14 in the closing direction. When the cover 1 is opened, contacts 11, 13 are closed and an ON electric signal is fetched to start an image pickup device (unshown).