PURPOSE: To provide a freezing cycle controller which never deteriorates the stability of the freezing cycle even in the different environments of application and needs no adjustment of the control gain even in the different installing conditions.

CONSTITUTION: When the overheating degree is controlled to be fixed at a target level by a control loop which controls the flow of refrigerant of a freezing cycle A by the opening amount of an electronic expansion value 6, an overheating degree state deciding mechanism 21 monitors the deviation between the overheating degree of the cycle A and a target level. Then, a hunting state is decided if the deviation is larger than a hunting deciding set level. If the state is judged to a hunting state, the gain G of the control loop is changed by a scaling change mechanism 22.