To avoid discriminating to be out-of-zone of a mobile station caused by an initial frequency error by shortening the time until P-CCPCH detection is made.

A frequency error detecting section 7 inputs base-band signals of demodulated in-phase and quadrature components and finds the squared values of the values of the signals. When the values of the signals are squared, the squared values become values which are not affected by modulated phases. The detecting section 7 finds the squared values several times and detects the initial frequency error from the found values. In addition, when an SCH is made to be a channel to be detected, the error between the frequency of a carrier wave and the frequencies of cosine and sine waves used for demodulation can be eliminated in the stage of the SCH.