A signal processing part 107 sets the operation start electric field value of AGC(automatic gain control) according to the measurement result of an error rate measuring circuit 109 which measures the error rate of a receive signal and makes a gain control circuit 106 start gain control when the electric field intensity detected by an electric field intensity detector 105 reaches the operation start, electric field value. Consequently, the optimum operation start electric field value of AGC can be set according to the radio wave state in which a radio receiver is placed, i.e., the reception state of the receive signal and the gain control of a gain control means can be performed so that the received signal has the best quality even in a state of IM characteristics or electric field variation characteristics, e.g. in environment of an intense electric field or large electric field variation. |