A radiator (5) in which core units (31-33) are arranged next to each other on a lower main tank (16) and an upper main tank (15) is placed at a position offset from the lower main tank (16) in a plan view. An upper sub-tank (35) of each core unit (31-33) is placed at substantially the same height as the upper main tank (15), and a side face of the upper sub-tank (35) is connected to a side face of the upper main tank (15) by a cooling water pipe (60). The upper main tank (15) has a cooling water inlet on the lower surface side.
