To attain more accurate equalization with a simple configuration by providing a means Fourier-transforming an input signal, detecting an attenuation of the signal in terms of a line spectrum and equalizing the line spectrum.

An attenuation detection section 13 detects an attenuation of an input analog signal from a received digital signal, and a control section 104 selects a desired coefficient for equalization based on the attenuation. On the other hand, A digital signal given to a Fourier transformation section 102 obtains spectrums relating to a fundamental frequency f0 with respect to a sampling period T and a frequency being an integer multiple of the frequency f0 and the spectrum is given to a √(f) AGC processing section 105. The processing section 105 calculates a product between the line spectrum and a desired coefficient from a control section 104 with respect to the frequency of the line spectrum to obtain an equalization line spectrum equalized in a Fourier space. The equalization line spectrum is given to an inverse Fourier transformation section 106, in which the spectrum is subject to inverse Fourier transformation and from which the equalized digital reception data are obtained.