A polar modulation transmission apparatus comprising: a power amplifier for amplifying power of a phase component signal of a predetermined signal; a power supply; a regulator for changing a power supply voltage of the power supply according to an amplitude component signal of the predetermined signal and supplying the power supply voltage to a power supply input terminal of the power amplifier; a current detecting section for detecting a value of current flowing from the power supply to the power amplifier; a power control section for limiting a value of a transmission power control signal specifying transmission power, based on the current value detected in the current detecting section; and a power apply section for adjusting a level of the amplitude component signal of the predetermined signal based on the transmission power control signal outputted from the power control section, characterized in that the power control section further comprises: a supply power estimating section for estimating a supply power supplied to the power amplifier based on the current value detected in the current detecting section and the transmission power control signal; and a comparison section for comparing the supply power to a predetermined threshold, wherein when the result of comparison in the comparison section shows that the supply power is greater than the predetermined threshold, the power control section is arranged to limit the value of the transmission power control signal. a power amplifier for amplifying power of a phase component signal of a predetermined signal; a power supply; a regulator for changing a power supply voltage of the power supply according to an amplitude component signal of the predetermined signal and supplying the power supply voltage to a power supply input terminal of the power amplifier; a current detecting section for detecting a value of current flowing from the power supply to the power amplifier; a power control section for limiting a value of a transmission power control signal specifying transmission power, based on the current value detected in the current detecting section; and a power apply section for adjusting a level of the amplitude component signal of the predetermined signal based on the transmission power control signal outputted from the power control section, characterized in that the power control section further comprises: a supply power estimating section for estimating a supply power supplied to the power amplifier based on the current value detected in the current detecting section and the transmission power control signal; and a comparison section for comparing the supply power to a predetermined threshold, wherein when the result of comparison in the comparison section shows that the supply power is greater than the predetermined threshold, the power control section is arranged to limit the value of the transmission power control signal. a supply power estimating section for estimating a supply power supplied to the power amplifier based on the current value detected in the current detecting section and the transmission power control signal; and a comparison section for comparing the supply power to a predetermined threshold, wherein when the result of comparison in the comparison section shows that the supply power is greater than the predetermined threshold, the power control section is arranged to limit the value of the transmission power control signal.