PURPOSE: To improve the processing capacity of a device by using flash light and to constitute the compact and light-weight device by fixing light receiving device for detecting the flash light and a reading means on a moving frame and moving the moving frame.

CONSTITUTION: The light receiving device 14a, 14b for detecting flash light and the reading means 15 for obtaining an image signal are fixed on the moving frame 16. The moving frame 16 is moved, and at the time of irradiation of radiant rays 2, the light receiving device 14 are arranged on positions proper to the reception of the flash light, and at the time of reading, the approximately whole areas of an accumulative fluorescent panel 12 are scanned with an optical beam 23. Consequently, the moving mechanism is almost equivalent to the moving mechanism of only the reading means 15, and since flash light can be utilized, the processing capacity of the device can be improved and the compact and light-weight device can be obtained.