A desired SIR control part presets the desired SIR value in a way that it decides to this end the degree of follow-up of the desired SIR by the received SIR (measured value), by reading out a desired communication quality value from a demodulating part, reading out a measured communication quantity value from a communication quality measuring part, reading out a desired SIR value from a memory and reading out a measured SIR value from an SIR measuring part. Thus, it is possible to quickly and smoothly cope with the occurrence of a change in the communication environment in the wireless communication in a W-CDMA system or the like between the base station and the mobile station.