To provide an operation method for an oil cooling compression type freezer wherein oil is properly circulated, and unnecessary residence of oil is eliminated.

An operation method for an oil cooling compression type freezer 1A is adapted to include a refrigerant circulation flow passage I containing an oil cooling compressor 11, an oil separation recovery apparatus 12, a condenser 13, an expansion valve 14, and a vaporizer 15. Further, the method is adapted in such a way that ordinary operation control is achieved to keep the number of revolutions of a driving section of the compressor 11 to a value suitable for a cooling heat load in the vaporizer 15. In the operation method, when the number of revolutions of the foregoing driving section is more reduced than the predetermined number of allowable minimum revolutions where oil is prevented from being mingled in the vaporizer, and continuous operation time in the low speed revolution state reaches predetermined allowable limit time, there is preferentially performed oil return control in which the number of revolutions is increased up to the foregoing number of minimum proper revolutions, and the operation is executed for a predetermined time where the oil can be returned to the compressor 11.