An image capturing apparatus for capturing an image of an object. The image capturing apparatus includes a correspondence detector which detects a correspondence of characteristic points of an object based upon captured images of the object. A motion detector detects a motion of the image capturing device. The motion detector includes magnetic sensors. Further, a shape calculator calculates a shape of the object based upon the captured image data, captured attitude information, a translation component, and the correspondence of the characteristic points. The motion detector may further include acceleration sensors and angle speed sensors. A disturbance detector may further be provided to detect a disturbance in acceleration signals output by the acceleration sensors and a disturbance in magnetic signals output by the magnetic sensors. In this situation, if a disturbance arises in the acceleration signals output by the acceleration sensors, an attitude of the image capturing apparatus can be based on signals output by the magnetic sensors and signals output by the angle speed sensors. Similarly, if a disturbance arises in the magnetic signals output by the magnetic sensors, an attitude of the image capturing apparatus can be determined utilizing the acceleration signals output by the acceleration sensors and the angle speed signals output by the angle speed sensors.