Image stabilization, which shifts the center of an image sensing device radially away from the optical axis of an imaging lens is performed multiple times in one frame. A path in a case where the movement of the center of the image sensing device at this time is viewed from the front is generated. A turning point, at which there has been a change in direction from the positive direction to the negative direction or vice versa along the vertical or horizontal direction, is detected in the path generated. The positional relationship between the position of the center of the shifted image sensing device and the optical axis of the imaging lens is determined from the turning point detected. Optical distortion of the image of the subject is corrected by utilizing this positional relationship.