An area image sensor outputs the difference between charges received by light-receiving cells arranged in an array pattern. A system controller generates a timing signal for generating a pulse or modulation signal. A control signal generator generates a control signal for separately controlling the light-receiving timings of the light-receiving cells of the area image sensor on the basis of the timing signal from the system controller. A light emitting controller controls a light source to generate light, the intensity of which changes on the basis of the timing signal from the system controller. A reflected light image processor extracts a reflected image of an object from the difference outputted from the area image sensor.