A left-side FPC accommodating aperture (16A) for inserting an FPC (24) into a left-side electronic component accommodating part (16) is provided at the side of a left-side hinge part (8) of the left-side electronic component accommodating part (16). A left-side waterproof member (26) comprising PORON (trademark) or the like which inhibits infiltration of moisture, dust, and the like into a battery part (20) is incorporated in the vicinity of a left-side connector part (25), i.e. a part connecting the FPC (24) and the battery part (20). A right-side FPC accommodating aperture (19A) for inserting the FPC (24) into a right-side electronic component accommodating part (19) is provided at the side of a hinge part (9) of the right-side electronic component accommodating part (19). A right-side waterproof member (28) comprising PORON (trademark) or the like which inhibits infiltration of moisture, dust, and the like into an electrical circuit part (21) is incorporated in the vicinity of a right-side connector part (27), i.e. a part connecting the FPC (24) and the electrical circuit part (21).
