The purpose of the invention is to reduce Cartesian loop transmission delay for compensating the distortion occurring in a high-frequency power amplifier and make the distortion compensation converge quickly, thereby increasing the efficiency. A transmission device has: a high-frequency power amplifier; a pre-distortion compensation circuit for independently generating the coefficients of the distortion compensation signal for each order of the odd and even symmetric distortions of the high-frequency power amplifier; a means for varying the power supply voltage of the high-frequency power amplifier with an orthogonal modulation OFDM input signal; a digital frequency converter; a high-frequency band ADC; and a high-frequency band DAC. In the transmission device, an error distortion compensation signal is created from the output of the high-frequency power amplifier and the orthogonal modulation OFDM input signal, and a delay device is inserted at the previous stage of a distortion compensation circuit, said delay device having a delay equivalent to a time constant for varying the power supply voltage of the high-frequency power amplifier with the orthogonal modulation OFDM input signal.