To accurately remove pilot signals contained in amplified signals outputted from amplifiers 3 to 7 in an amplifying device in which input signals and pilot signals are complexed into complex signals, the complex signals are amplified by amplifiers 3 to 7, the amplifiers 4, 5, and 7 are monitored on the basis of the pilot signals contained in the amplified signals outputted from the amplifiers 3 to 7, and the amplified input signals contained in the amplified signals are outputted.

An amplifying device is equipped with pilot signal removing means 1, 21, and 22 which complex pilot signals that are complexed with input signals with the amplified signals outputted from amplifiers 3 to 7 inversely in phase as to the pilot signals so as to remove the pilot signals contained in the amplified signals, and the amplifying device outputs the amplified signals from which the pilot signals have been removed by the pilot signal removing means 1, 21, and 22 as amplified input signals.