Abstract: An auto frequency control apparatus arranged to vary the division ratio of the comparison signal portion in the phase comparator with the AFC control voltage so as to change the frequency in order to make coincide the frequency of the output signal from a local oscillation portion and that of a carrier-wave signal for a frequency-shift keying signal with each other. The frequency of an output signal from a reference-signal generating portion is divided by a divider 213. The frequency of the output signal from a local oscillation portion is supplied to an auto frequency control 202. A control-signal processing portion 207 receives AFC control voltage to instruct an updown counter 205 to correct the division to correspond to the voltage. In accordance with the instruction, a counter 203 divides the supplied signal, the signal being multiplied with an integer in a multiplier 204 so as to be transmitted. The output signal is divided with a division ratio set by a divider 209.