An air conditioner, comprising a refrigerant circuit having a compressor, an indoor heat exchanger, a radiation heat exchanger, a decompression structure, and an outdoor heat exchanger, wherein: the indoor heat exchanger is provided inside an indoor unit so as to oppose to a fan; the radiation heat exchanger is provided on a surface of the indoor unit; the air conditioner further comprising a controller configured to increase or decrease the frequency of the compressor based on a temperature difference between an indoor target temperature and an indoor temperature; the air conditioner is capable of performing a warm-air heating operation that performs warm-air heating by causing the refrigerant to flow not in the radiation heat exchanger but in the indoor heat exchanger, and a radiation heating operation that causes the refrigerant to flow in the indoor heat exchanger to perform the warm-air heating and causes the refrigerant to flow also in the radiation heat exchanger to perform radiation heating; and timings at which the controller increases or decreases the frequency of the compressor during the radiation heating operation and timings at which the controller increases or decreases the frequency of the compressor during the warm air heating operation, are made different from one another, characterised in that in cases where the temperature difference decreases, the controller starts decreasing control for decreasing the frequency of the compressor, when the temperature difference is decreased to a first switch value; and the first switch value in the radiation heating operation is smaller than the first switch value in the warm-air heating operation; and/or characterised in that in cases where the temperature difference increases, the controller starts the increasing control which increases the frequency of the compressor, when the temperature difference increases up to a third switch value; the third switch value in the radiation heating operation is smaller than the third switch value in the warm-air heating operation. the indoor heat exchanger is provided inside an indoor unit so as to oppose to a fan; the radiation heat exchanger is provided on a surface of the indoor unit; the air conditioner further comprising a controller configured to increase or decrease the frequency of the compressor based on a temperature difference between an indoor target temperature and an indoor temperature; the air conditioner is capable of performing a warm-air heating operation that performs warm-air heating by causing the refrigerant to flow not in the radiation heat exchanger but in the indoor heat exchanger, and a radiation heating operation that causes the refrigerant to flow in the indoor heat exchanger to perform the warm-air heating and causes the refrigerant to flow also in the radiation heat exchanger to perform radiation heating; and timings at which the controller increases or decreases the frequency of the compressor during the radiation heating operation and timings at which the controller increases or decreases the frequency of the compressor during the warm air heating operation, are made different from one another, in cases where the temperature difference decreases, the controller starts decreasing control for decreasing the frequency of the compressor, when the temperature difference is decreased to a first switch value; and the first switch value in the radiation heating operation is smaller than the first switch value in the warm-air heating operation; in cases where the temperature difference increases, the controller starts the increasing control which increases the frequency of the compressor, when the temperature difference increases up to a third switch value; the third switch value in the radiation heating operation is smaller than the third switch value in the warm-air heating operation.