In a remote controller, a conductive air mouse button (21) is electrically connected to one terminal (13a) of a battery (13). A conductive lower case (12, 41) is electrically connected to the other terminal (13b) of said battery (13). Light-emitting (17) and light-receiving (16) devices which transmit/receive radio signals when said air mouse button (21) and said lower case (12, 41) are contacted by fingers (100), to thereby be electrically connected to form a closed circuit.