To provide an echo canceller that returns no echo to a caller even a large change takes place in an echo path characteristic such as on-hook or off-hook of an opposite phone.

A 1st transmitter 11 is provided with a REP section 12 that relays a control signal to a 1st phone 2, a HYB transformer 13 that conducts 2/4 wire conversion, a 1st echo canceller 14a and a 2nd echo canceller 14b that cancel a circulated echo, changeover sections 15a, 15b that select and use the 1st echo canceller 14a and the 2nd echo canceller 14b, and a control section 16 that controls each component, and the 1st echo canceller 14a and the 2nd echo canceller 14b respectively comprise pseudo echo generating sections 17a, 17b respectively generating a pseudo echo and subtractors 18a, 18b that use the pseudo echo to cancel the echo.