PURPOSE: To designate a desired frame number at an optional place by providing a means for writing inputted frame position information in the specified area of a rewritable image information storing medium.

CONSTITUTION: An operator checks already developed film, selects the frame number which should be written in an MD 1 in advance, and successively inputs it from an operation part 3. The inputted frame number inputs a control part 5 through an MD interface 4, and the control part 5 stores the inputted frame number and successively displays it on a display part 6. The operator checks the frame number displayed on the display part 6 and confirms whether it is correctly inputted. In the case the frame number is correctly inputted, the operator gives a writing command from the operation part 3. When the control part 5 receives the command, it gives the stored frame number to an MD drive 2 through the interface 4 so as to write it in the specified area of the MD 1.