The present invention is directed to more accurately acquiring shape data than conventional techniques. After an imaging unit images an interference fringe, a calculation unit acquires the captured image from the imaging unit. The calculation unit extracts a ring zone region where the interference fringe is sparse in the captured image from each captured image, and calculates a phase distribution of the interference fringe in each ring zone region. The calculation unit acquires a deviation component having an orientation and an amount both unchangeable along a circumferential direction of a circle centered at the optical axis of the subject light by analyzing the interference fringe contained in each acquired captured image. Further, the calculation unit calculates positions of characteristic points of a calibrator, and calculates a distortion component. Then, the calculation unit calculates the shape data corrected based on the deviation component and the distortion component.
