A control section 200 executes photographing processing for controlling the light projecting section and the light receiving section to photograph a measurement object placed on a stage, contour extracting processing for extracting a contour of the measurement object from an image of the measurement object, storing processing for determining whether the measurement object is present in rectangular regions adjacent to a photographing visual field and causing a storing section to store coordinate positions of one or more of the rectangular regions where it is determined that the measurement object is present, driving processing for driving the stage-plane-direction driving section to move the photographing visual field to any one of the coordinate positions stored in the storing section by the storing processing, and coupled-image generation processing for generating a coupled image by coupling images of the rectangular regions adjacent to one another obtained by repeatedly executing the photographing processing.