A first control unit includes a first operation data generation section for generating first operation data in accordance with a motion of a first control unit body included in the first control unit. A second control unit includes a second operation data generation section for generating second operation data in accordance with a direction input operation performed by a player or a motion of a second control unit body included in the second control unit. Further, one of the first control unit and the second control unit includes a transmission section for transmitting the first operation data and the second operation data to a computer at a predetermined timing.