PURPOSE: To simplify the sequense control by providing a rotatable mirror, which reflects the light from the light source provided in each bin, and providing full-bin or empty-bin detectors that receive reflected light.

CONSTITUTION: Each bin 27A to 27C is provided with both a radiating element 40A to 40C for detecting being full or empty of each bin and a rotatable mirror 37A to 37C. By rotating a mirrro 37A in correspondence to the bin 27A that accommodates paper 50 around an axle 38 taken as a rotational center, the light from the radiation elements 40A and 40B provided in the bin 27A and the neighboring 27B is reflected in succession, and thus reflected light is made incident on a single detector 32A. With this contrivance, the number of detectors 32A can be decreased to ease the sequence control.