A power amplifying device includes an amplifier that amplifies a signal which is input in accordance with a voltage signal which is supplied to the amplifier, a voltage control section that controls the voltage signal in accordance with a transmission signal, a distortion compensating section that executes a distortion compensating process on the transmission signal by giving a value indicative of a reverse characteristic of the amplifier to the transmission signal in advance and inputs an output signal obtained by executing the distortion compensating process into the amplifier, an amplitude detecting section that detects an amplitude of the transmission signal, and a timing adjusting section that adjusts timings of the output signal and the voltage signal so that a value relating to the distortion compensating process meets a given condition when a detected value of the amplitude of the transmission signal is less than a given value.