To prevent degradation of equalization ability without being affected by noise components.

The noise components in a reception band are extracted by a BPF 90 and the reception level of the noise components is analyzed at all times in a detection circuit 91. When it is judged that the reception level of the noise components is higher than a prescribed level in a noise judgement device 92, a tap updating processing in an adaptive equalization part 81 is temporarily interrupted. When it is judged that the reception level of the noise components is lower than the prescribed level, the tap updating processing is restarted. Thus, abnormality or the like in a transmission route is easily detected and the degradation or divergence of the adaptability is prevented.