To provide a higher harmonic spread spectrum circuit of clock frequencies capable of easily spreading signals in a wide band in a simple constitution.

This higher harmonic spread spectrum circuit of clock frequencies is provided with a transmitter for outputting a clock signal, a CR integrator for integrating each clock signal while switching plural time constants, a control signal generator for outputting a control signal for selecting the time constant, and a waveform shaper for wave form-shaping the output signal of the CR integrator.