a frequency stabilization circuit includes a local oscillator , a mixer , a level comparator , a frequency comparator , and a controller . the local oscillator outputs a local oscillation signal in accordance with a control voltage . the mixer converts a received radio frequency signal into an intermediate frequency signal using the local oscillation signal from the local oscillator . the level comparator compares a dc voltage corresponding to the intermediate frequency signal from the mixer with a reference voltage to determine whether the reception electric field level of the radio frequency signal is high or low . the frequency comparator compares the frequency of the intermediate frequency signal from the mixer with the frequency of the reference signal to output frequency difference information . the frequency comparator outputs previous frequency difference information when the comparison result of the level comparator indicates a decrease in reception electric field level . the controller outputs the control voltage to the local oscillator in accordance with the frequency difference information from the frequency comparator .