A heat exchanger (1, 2, 10, 20) of a heat exchange device, a heat exchange module (100), a heat exchange device (65, 75, 115) and a heat source unit used for an air-cooling cold-water unit or a commercial roof machine. The heat exchanger (1, 2, 10, 20) comprises: a main body (15, 65, 75, 115) having a substantially quadrilateral side surface ; bent parts (16, 17, 66, 67, 76, 77, 116, 117) connected to the main body (15, 65, 75, 115), and at least one of bent parts (17, 67, 77, 117) having a substantially quadrilateral side surface; when there being two bent parts (16, 17, 66, 67, 76, 77, 116, 117), one bent part (17, 67, 77, 117) having a substantially quadrilateral side surface, and the other having a substantially trapezoidal side surface ; at least one heat exchange tube (13) extending between the main body (15, 65, 75, 115) and the bent part (16, 17, 66, 67, 76, 77, 116, 117), and the heat exchange tube (13) in the bent part (16, 17, 66, 67, 76, 77, 116, 117) being inclined and bent relative to the heat exchange tube (13) in the main body part (15, 65, 75, 115), so that the plane in which the main body (15, 65, 75, 115) lies being perpendicular or substantially perpendicular to the plane in which each of two bent parts (16, 17, 66, 67, 76, 77, 116, 117) lies. The heat exchanger (1, 2, 10, 20), the heat exchange module (100), the heat exchange device (65, 75, 115) and the heat source unit can effectively utilize the space between the heat exchanger (1, 2, 10, 20).