A heat source-side heat exchanger fan blowing air to a heat source-side heat exchanger performing heat exchange with refrigerant compressed in a compressor is controlled. A current detected temperature at a current time is converted to obtain a current converted high pressure value at the current time. The current converted high pressure is a pressure of refrigerant inside a high pressure-side pipe of the compressor. The current detected temperature is a temperature detected by a temperature detector attached to the heat source-side heat exchanger. A past detected temperature is converted to obtain a past converted high pressure value at the past time. A speed of the heat source-side heat exchanger fan is determined using a corrected converted high pressure value. The corrected converted high pressure value is obtained by correcting the current converted high pressure value based on the past converted high pressure value.