To surely identify the truth/false of paper sheets in simple configuration by irradiating the paper sheets with ultraviolet rays, detecting visible light due to fluorescent reaction from reflected light and discriminating the paper sheets as false when there is a fluorescent output except for a fluorescent reaction part formed on the paper sheets.

Inserted paper sheets 1 are irradiated with ultraviolet rays A by an ultraviolet irradiating device 3, and the visible light due to the fluorescent reaction is detected out of reflected light B from the paper sheets 1 irradiated with the ultraviolet rays by a visible light photodetection sensor 4. A discrimination part 6 connected to the visible light photodetection sensor 4 discriminates a paper money as false when there is the fluorescent reaction over the entire paper money in the visible light detected by the visible light photodetection sensor 4. In this case, the ultraviolet irradiating device 3 and the visible light photodetection sensor 4 are arranged at positions for irradiating the surface of a path line on a fluorescent reaction part 2 of the paper sheets 1 with the ultraviolet rays A from the ultraviolet irradiating device 3 and photodetecting its reflected light B through the visible light photodetection sensor 4.