PURPOSE: To attain the transmission with high quality and simple hardware constitution in a line having a rapid fading fluctuation by integrating fading distortion compensation and maximum ratio synthesis space diversity synthesis in the multi-value quadrature amplitude modulation system.

CONSTITUTION: A transmission line distortion estimate section 29 estimates a transmission line distortion of each branch from a reception base band signal in a frame timing. A phase compensation section 30 based on an obtained phase fluctuation estimate value compensates the phase distortion due to fading of a reception signal of each antenna to make phases of signals of each antenna in-phase. A synthesis section 31 applies weighting proportional to the amplitude fluctuation of each antenna due to fading obtained in this way and applies synthesis. A decoding section 32 calculates the discrimination threshold level after synthesis to decode a data. Thus, the transmission with high quality and simple hardware constitution is attained.