PURPOSE: To obtain the FM modulation circuit reducing a distortion factor in a demodulation characteristic without increasing a current of a compensation circuit.

CONSTITUTION: An output signal of a frequency divider 15 in a PLL loop of a PLL circuit 10 and a signal of a reference oscillator 17 are compared by a phase comparator 161 comprising a counter 161a and a D/A converter 161b, a compared output and an input signal are added and the sum is used for a frequency control signal of a VCO 13. The output of the VCO 13 is fed to the frequency divider 15 and extracted at an output 14 as a modulation output. The counter 16a stops its count by a control signal from a control terminal 20.