After a housing of a cassette is opened by a suction cup, then a stimulable phosphor sheet is removed from the cassette by a shiftable roller and then fed in an auxiliary scanning direction by a feed mechanism. While being fed in the auxiliary scanning direction, the stimulable phosphor sheet is irradiated with a laser beam emitted from a stimulating optical system. Light emitted from the stimulable phosphor sheet upon exposure to the laser beam is guided through a light guide to a photoelectric transducer. After the recorded radiation image information is read from the stimulable phosphor sheet, the stimulable phosphor sheet is stored back into the cassette, and erasing light from erasing light sources is applied to the stimulable phosphor sheet in the cassette to erase remaining radiation image information from the stimulable phosphor sheet.