To output a signal with high phase accuracy at high power efficiency even in the case of using a power amplifier having a non-linear characteristic because a phase delay can be controlled by a phase difference signal and to simplify the constitution of this transmitting circuit by using a circuit including the phase delay in an orthogonal modulator.

A signal modulated by a digital modulator 1 is modulated to a carrier by an orthogonal modulator 2. The modulated carrier modulated by the modulator 2 is amplified by a power amplifier 4 through an amplifier 3 and the amplified carrier is outputted to an output terminal 6 through a power distributor 5. A reference signal 9 outputted from the modulator 1 is given to the input terminal of a phase comparator 10 and a part of the modulated carrier outputted from the distributor 5 is envelop-detected by a detector 7 and given to the input terminal of the comparator 10. A difference signal is generated from the two signals inputted to the comparator 10 and outputted from the comparator 10 and the voltage of the difference signal is amplified by a level conversion circuit 11 to control a phase delay 12 built in the modulator 2.