PURPOSE: To form the lop antenna in diversified forms through the change in the shape of a cabinet face and to improve the assembly job performance by forming the loop antenna while conductor plating is applied to the cabinet face.

CONSTITUTION: Conductor plating such as copper plating is applied from an inner face of a cabinet 1 over one side of a rib 2 and further a photo resist is coated on the plating. Then mask processing is applied to obtain a shape of the loop antenna and exposure and development is applied by using an ultraviolet ray to allow only the shape of the loop antenna to have the resist and the loop antenna 3 by a copper foil pattern is formed on a cabinet 1 through the etching processing. Since the rib 2 at which both ends 5 of the loop antenna 3 are placed is located at a position inserted to a slit antenna mount hole 6 of a board 4, both the ends 5 and the pattern on the printed circuit board 4 are soldered to connect electrically the loop antenna 3 to a transmission reception circuit on the printed circuit board 4.