A paper sheet recognition apparatus can generate a subtracted reflective light image without increasing detection time. To that end, the operations of sensors are controlled in a plurality of phases. The phases include a phase (reflected infrared light 1) in which a first light emission unit emits light, a second light emission unit emits no light, and an optical sensor detects reflective light. In another phase, (reflected infrared light 2) the first light emission unit emits no light, the second light emission unit emits light, and the optical sensor detects reflective light. In at least one of these phases, a light emission unit emits light, and an optical sensor detects transmissive light.