PURPOSE: To reduce labor and time required for manufacture and adjustment and to lower a price by correcting an oscillation frequency in a device side processor based on information inside a memory.

CONSTITUTION: The processor 16 supplies the information of a first temperature to the memory 15, the information is simultaneously read in a microcomputer 103 and transmitted through a D/A 102 to a thermostatic chamber temperature control part 101 and thus, a temperature inside a thermostatic chamber is turned to the first temperature. When the first temperature is reached inside the chamber, in the processor 16, the oscillation output frequency of OC×O is highly accurately measured and stored in a storage device attached to the processor. Then, the information of a second temperature higher than the first temperature is supplied to the memory 15, the temperature inside the chamber is turned to the second temperature similarly, then, the oscillation output frequency of OC×O is measured and a difference with the frequency at the first temperature is obtained and recorded. Similar control is successively executed with a prescribed temperature gap and (n) (n≥3) pieces of frequency-temperature data are obtained.