Light is emitted on one side of a paper sheet 100, which is being transported on a transport path, from a first light source 11, and light is emitted on other side of the paper sheet 100 from a second light source 21 and a fourth light source 22. A first light receiving sensor 14 receives a first reflected light, which is the light emitted by the first light source 11 and reflected from the one side of the paper sheet 100. A second light receiving sensor 24 receives a second reflected light, which is the light emitted by the second light source 21 and the fourth light source 22 and reflected from the other side of the paper sheet 100, and receives a transmitted light that is the light emitted by the first light source 11 and that has passed through the paper sheet 100. With this, satisfactory reflection image and transmission image of the paper sheet can be acquired while realizing the downsizing of the device.