An AGC circuit for a radio receiver includes a detector converting a high frequency signal into a baseband signal. To reduce generation of a DC offset, the AGC circuit includes: a variable gain amplifier having an amplifier circuit and a high-pass filter, the amplifier circuit amplifying the baseband signal with a variable gain and the high-pass filter coupled to the amplifier circuit and having a cut-off frequency which is variable; a controller supplying a gain control signal; and a blocker temporarily blocking the high frequency signal. Using the block control signal, the controller causes the blocker to start blocking the high frequency signal, before the cut-off frequency of the high-pass filter is switched from high to low.