To improve an operation control system for an inside cooling/heating device for a vending machine adopting a heat pump refrigerator for the sales of cold/hot commodities, so that the device maintains stable operation by preventing the overload and lower operating efficiency of the refrigerator in an operation mode for the sales of the hot commodities.

The inside cooling/heating device comprises an outside unit consisting of a compressor, an outside heat exchanger and an outside fan combined and an inside unit consisting of an expansion mechanism, an inside heat exchanger and an inside fan combined, arranged in a commodity chamber. It is constructed with the heat pump refrigerator for cooling/heating inside stored commodities with cold/heat generated by its refrigerating cycles. In the operation mode where at least one inside heat exchanger is used as a condenser for radiating heat, the rotating number of the blowing fan of the heat exchanger as an evaporator for absorbing heat is changed to control the quantity of absorbed heat in accordance with a detection signal from an inside temperature sensor, preventing increases in condensation temperature and the quantity of radiated heat over preset values.