An acquisition section 100 acquires a mouse operation signal. A dead zone adjustment section 126 adds a signal part corresponding to a dead zone set to an analog stick, to the mouse operation signal. An analog stick operation signal generation section 128 generates an analog stick operation signal from the mouse operation signal having been subjected to dead zone adjustment. An output processing section 150 provides the generated analog stick operation signal to a game. The dead zone adjustment section 126 adds the signal part corresponding to the dead zone in a direction in which an operation angle of a mouse is maintained.