To provide a clock control circuit, a demodulation device, and a spread spectrum method, which can reduce interference caused by a clock signal on which spread spectrum is performed when demodulating a signal. A clock controller 22 according to the present invention disperses a harmonic of a clock signal in a used frequency band of a reception signal and controls a harmonic remaining in the used frequency band after the dispersion. For example, the clock controller 22 controls an amplitude of the harmonic on the basis of a spread frequency used for the dispersion and a spread width of the harmonic.