To improve the characteristic of radio communication by estimating a Doppler frequency with high accuracy.

A complex time response signal measuring section 11 measures the complex time response signal of a propagation path for each radio frame period. A phase difference calculating section 12 determines an absolute value of the complex time response signal serving as a candidate. The maximum complex time response signal corresponds to the complex time response signal serving as a candidate. Further, when the maximum complex time response signal moves frequently, the timing of generating the maximum complex time response signal is fixed and an absolute value of a phase difference at the same timing is determined. An averaging section 13 determines an average value by averaging the absolute values of phase differences over a plurality of radio frames. A Doppler frequency estimating section 14 divides the average value by the time interval of the radio frames to estimate a Doppler frequency.