Abstract: A detecting system for a surface form of an object is disclosed. The system comprises a light source section emitting a plurality of slit-like probe rays incidenting on a predetermined inspected area of an inspected object at predetermined pitches, an image pick-up section imaging reflected lights of the probe rays from the inspected area, the image pick-up section imaging the reflected lights from a direction different from a transmission axis of the light source section, the image pick-up section disposed so as to image the reflected light from the inspected area in a batch, and a computation section converting image data from the image pick-up section into data of surface height of the inspected object using a trigonometrical survey method.