To compensate the temperature of a frequency with inexpensive constitution.

A first oscillator 11 generates a first oscillation signal. A second oscillator 12 generates a second oscillation signal whose frequency characteristic differs from that of the first oscillation signal. A deviation generation part 13 receives the first and second oscillation signals, obtains a relative change rate against an environment temperature between the first and second oscillation signals and makes it to be a deviation. A programmable frequency divider 15 frequency-divides the first oscillation signal and separates a clock signal. The temperature characteristic of a first oscillation signal frequency against the environment temperature and a relative change rate are previously set in a memory 16. CPU 15 controls the programmable frequency divider based on the content of the memory when the deviation is received and compensates the temperature of a clock signal frequency.