In a signal separation circuit for separating a plurality of pulse signals received via the same signal line, a PC-on signal detection circuit detects a PC-on signal with a first pulse width from a PC/TV-on signal received via the signal line and generates a first corresponding output signal. A TV-on signal detection circuit detects a TV-on signal with a second pulse width shorter than the first pulse width from the PC/TV-on signal and generates a second corresponding output signal.