There are provided an A/D converting circuit (10) for converting, into a digital signal, a broadband intermediate frequency signal which is output from a frequency converting circuit (5), and a DSP (11) for generating and outputting control data to control gains of an antenna damping circuit (3) and an LNA (4) based on a level of the broadband digital intermediate frequency signal which is output from the A/D converting circuit (10), and the broadband intermediate frequency signal which is output from the frequency converting circuit (5) is A/D converted and supplied to the DSP (11). Consequently, it is possible to reduce a frequency of a signal input to the A/D converting circuit (10). Thus, it is also possible to reduce a consumed current without requiring the use a special AD converter corresponding to a radio frequency input.