Abstract: Disclosed is a control device for controlling power level between frequency assignment in an RF receiving device of a mobile radio communication base station system in a CDMA system capable of lowering the power level of the frequency assignment signal having a relatively high power difference, after the detection of the power level by the frequency assignment, to thereby minimize the power level difference between the frequency assignment and then, executing an AGC for three frequency assignment, whereby the performance deterioration of the whole channels, which is caused due to the disappearance of the frequency assignment signal having a relatively low power difference by the frequency assignment having the high power difference, can be prevented.