Polar modulation transmission apparatus capable of suppressing power loss of a battery supply line to a high-frequency power amplifier regardless of whether transmission power is high or low is provided. Operation control section (120) performing control in such a manner that a battery voltage (S21) converted as a result of operation of a DC/DC converter (111) is applied to amplitude signal amplifying section (106) or halting operation of the DC/DC converter (111) in such a manner that battery voltage (S20) is applied directly from the battery (130) based on a transmission power control signal (S14). As a result, when transmission power is low, power loss at the amplitude signal amplifying section (106) is suppressed by DC/DC converter (111), unnecessary operation of DC/DC converter (111) is halted when transmission power is high, and power loss can be suppressed regardless of whether transmission power is high or low.