To provide a stable oscillation frequency by automatically setting frequency deviation to 0 ppm for each oscillator, and also to provide further a stable oscillation frequency by also taking temperature deviation into account.

A system controller 10 is shifted to an adjustment mode for adjusting the oscillation frequency of a crystal oscillator Z by oscillating the relevant crystal oscillator Z in timing when a frequency counter 101 is connected to a connecting terminal T4, or on the basis of an instruction signal from a remote controller 11. The application voltage of a control terminal T3 is controlled in such a way that the oscillation frequency counted by the frequency counter 101 matches a reference oscillation frequency being set internally, an application voltage value in matching is stored in a flash memory 6, and the adjustment mode is ended. When a device is operated thereafter, the application voltage value stored in the flash memory 6 is applied from the control terminal T3, and a clock signal is acquired from an oscillation circuit 17.