A solar panel of the present invention, above which pointers mounted on a pointer shaft inserted into a through hole provided at the center of the solar panel move, includes a center cell circularly formed around the through hole and a plurality of outer-circumferential cells formed around the outer periphery of the center cell in a manner to have substantially same light-receiving areas. The center cell is formed to have a light-receiving area larger than the light-receiving area of each outer-circumferential cell, taking into consideration a light-shielding area where the pointers overlap with the center cell. Therefore, even though the pointers always overlap with the center cell and part of the pointers overlaps with one of the plurality of outer-circumferential cells, the fluctuation of each light-receiving area of the center cell and the plurality of outer-circumferential cells due to this overlap can be minimized.