PURPOSE: To obviate long and continuous electric wires for transmitting signals, get rid of the malfunction of a control circuit unit due to noise and improve the temperature regulating function of the present chamber by a method wherein light emitting elements and photo detectors are provided in the control circuit unit, regulating a temperature in the present chamber, while optical fibers, connecting both of the elements, are arranged in the vicinity of a temperature detecting unit.

CONSTITUTION: Optical fibers 16a-16d are arranged between a temperature detecting unit 11 in the main body 1 of a storage chamber and a control circuit unit 15, arranged in a machine room 9. Two pieces of light emitting elements 18, 19 and two pieces of photo detectors 20, 21 are mounted on a print substrate 17 constituting the control circuit unit 15 while both of the elements and detectors are connected through the optical fibers 16a-16d to form photo couplers. When both of the photo detectors 20, 21 are put ON, the operation of a compressor 10 is started and when both of the photo detectors are put OFF, the operation of the compressor 10 is stopped. A bellows 26 is attached to a temperature sensitive cylinder 12 of the temperature detector 11 while a reflecting plate 27, operated in accordance with the contraction and/or expansion of the bellows 26, is attached to the bellows 26 and the arranging position of the end faces of the optical fibers 16a-16d are moved in parallel to the moving direction of the reflecting plate 27 whereby the setting of a temperature in the chamber can be changed.