A heat exchanger, comprising: a first manifold and a second manifold disposed on the same side of the heat exchanger; and a plurality of flat heat exchange tubes, each heat exchange tube having: a first heat exchange part and a second heat exchange part which are substantially parallel; and a first end and a second end connected to the first heat exchange part and the second heat exchange part respectively, the first end deviates from a center line of the first heat exchange part by curving, such that the first end and the second end are connected to, and in fluid communication with, the first manifold and the second manifold respectively, the first heat exchange part and the second heat exchange part are arranged in a first direction, and extend in a second direction which is substantially perpendicular to the first direction, and said same side of the heat exchanger is the same side in the second direction, in a plane defined by the first direction and the second direction, characterised in that each heat exchange tube further has a connecting part connecting the first heat exchange part and the second heat exchange part; at least one of the connecting parts is a U-shaped tube, or at least one heat exchange tube is an integral whole and the connecting part of the at least one heat exchange tube is formed by bending, fins are disposed between the first heat exchange part and the second heat exchange part. a first manifold and a second manifold disposed on the same side of the heat exchanger; and a plurality of flat heat exchange tubes, each heat exchange tube having: a first heat exchange part and a second heat exchange part which are substantially parallel; and a first end and a second end connected to the first heat exchange part and the second heat exchange part respectively, the first end deviates from a center line of the first heat exchange part by curving, such that the first end and the second end are connected to, and in fluid communication with, the first manifold and the second manifold respectively, the first heat exchange part and the second heat exchange part are arranged in a first direction, and extend in a second direction which is substantially perpendicular to the first direction, and a first heat exchange part and a second heat exchange part which are substantially parallel; and a first end and a second end connected to the first heat exchange part and the second heat exchange part respectively, the first end deviates from a center line of the first heat exchange part by curving, such that the first end and the second end are connected to, and in fluid communication with, the first manifold and the second manifold respectively, the first heat exchange part and the second heat exchange part are arranged in a first direction, and extend in a second direction which is substantially perpendicular to the first direction, and said same side of the heat exchanger is the same side in the second direction, in a plane defined by the first direction and the second direction, characterised in that each heat exchange tube further has a connecting part connecting the first heat exchange part and the second heat exchange part; at least one of the connecting parts is a U-shaped tube, or at least one heat exchange tube is an integral whole and the connecting part of the at least one heat exchange tube is formed by bending, fins are disposed between the first heat exchange part and the second heat exchange part.