An image detecting apparatus includes an illumination system and a sensing system. The illumination system is for providing a light beam to a working surface to generate a reflected light beam by the working surface. The sensing system includes a sensing unit and a condensing unit. The sensing unit is disposed on a transmission path of the reflected light beam reflected by the working surface for receiving the reflected light beam. The condensing unit is disposed between the sensing unit and the working surface, wherein an optical axis of the condensing unit is deviated from a main optical axis of the reflected light beam.