PURPOSE: To prevent system capacity from being reduced even in a mobile station disabled to deal with a power control instruction from a base station.

CONSTITUTION: The base station 2 is provided with a signal intensity detecting means 30 which detects the signal intensity of reception signals from plural mobile stations 1a, 1b,..., 1n to which inverse diffusion processing is applied by using a proper code allocated to each mobile station, a mean value calculating means 31 which calculates the mean value of the signal intensity detected by the signal intensity detecting means 30, a disturbance reception signal detecting means 32 which detects a disturbance reception signal with signal intensity exceeding the mean value by a prescribed value, a demodulation means which demodulates the disturbance reception signal detected by the disturbance reception signal detecting means 32, a spread modulation means 33 which performs the spread modulation of a signal demodulated by the demodulation means, a level adjusting means 34 which adjusts the level of a spread signal obtained at the output side of the spread modulation means 33, and a subtractor means 35 which sets the level of the disturbance reception signal as the mean value by subtracting the spread signal from the disturbance reception signal.