A reflective photosensor detects a target object. The photosensor includes a transparent circuit board, a light emitter and a light receiver on one surface of the circuit board, including a light emitting element and a light receiving element, respectively, and disposed so that the light emitting element and the light receiving element face the one surface, a concave portion on the other surface of the circuit board, including a first refractive face to oppose the light emitting element and refract light from the light emitting element to the light receiving element and a second refractive face to oppose the light receiving element and refract, to the light receiver, a component of the light refracted by the first refractive face and specularly reflected by the target object.