A wireless communications device comprises a common amplifier for amplifying a plurality of high-frequency signals of different communications systems, a plurality of signal channels provided subsequent to the common amplifier, each of the plurality of high-frequency signals being passed through the respective signal channels, and a switch circuit provided between the plurality of signal channels and the common amplifier, for connecting the common amplifier and one of the plurality of signal channels. Each of the plurality of signal channels is provided with a power amplifier having power amplification efficiency optimal with respect to a high-frequency signal passed through the signal channel.