The invention discloses an air conditioner. The air conditioner comprises an air-conditioning system and a solution circulating system, and the solution circulating system has a dehumidifying mode and a humidifying mode; the air-conditioning system comprises a compressor, a four-way valve, an indoor heat exchanger, an outdoor heat exchanger and a throttling device, and the solution circulating system comprises a dehumidifying device and a regenerating device; when the solution circulating system is in the dehumidifying mode, a pipeline between the inlet end of the dehumidifying device and the outlet end of the regenerating device is in heat exchange connection with an air-return pipeline of the compressor through a first heat exchanger; the first heat exchanger comprises an outer pipe and an inner pipe, the inner pipe is sleeved with the outer pipe, the outer circumferential wall of the inner pipe and the inner circumferential wall of the outer pipe are arranged in a spaced manner, diversion plates are arranged between the inner pipe and the outer pipe, the diversion plates axially extend in the extending direction of the inner pipe, the diversion plates are arranged on the inner pipe, an upwards opened containing groove is formed between each diversion plate and the inner pipe, and a flow passing interval for enabling a liquid to flow to the bottom of the outer pipe is formed between each diversion plate and the outer pipe.