A heat exchanger includes heat exchange fins, refrigerant pipes are arranged across the heat exchange fins, and connecting pipes connected to the refrigerant pipes to thereby define refrigerant passages. The connecting pipes include a first pipe portion having a first end connected to one of the refrigerant pipes, a branch pipe portion that is branched from the first pipe portion, that extends parallel to the first pipe portion, and that is connected to another of the refrigerant passages, and a second pipe that is connected to the first pipe portion and that is configured to guide gas-phase refrigerant separated from the refrigerant in the first pipe portion. The second pipe includes an inner insert portion inserted into a second end of the first pipe portion and an outlet portion that extends from the inner insert portion in direction opposite to the second end of the first pipe portion.