RF input signals having mutually different carrier frequencies are input from a signal generator to a power amplifier, the power amplifier amplifying the RF input signals and outputting them as RF output signals. The signal generator has a function for reducing the PAR of the waveform combining the RF input signals. The PAR reduction of the combined waveform of the RF input signals is performed through a control on the transmission timing of the RF input signals via a delay adjuster installed in the signal generator, or through an amplitude constraint on the RF input signals via a limiter installed in the signal generator. In this manner, a transmission device with improved power efficiency is provided.