A transmission apparatus of the present invention includes polar modulator (601) that generates a power supply modulation signal and RF signals of a plurality of carrier frequency bands to be transmitted, power amplifier (603) that amplifies the RF signals from polar modulator (601), and power supply modulator (602) that modulates the power supply terminal of power amplifier (603) by a signal obtained by amplifying the power supply modulation signal from polar modulator (601). The power supply modulation signal is set based on a function using, as an argument, the power of the RF signal of each carrier frequency band output from power amplifier (603).