PURPOSE: To facilitate assembling of parts and to improve the manufacture efficiency by assembling a plurality of U-shaped openings forming both upper and lower ends of the main body integrally with end blocking tools which alternately blocks the opening and blocking gaps of respective fitting portions using a bonding agent or the like.

CONSTITUTION: Bridge portions 33 are inserted into U-shaped openings 12 from the left lower side toward the right upper direction. Claws 34 are inserted and fitted into the interiors of U-shaped vertical lines 13, and a region confronting the claws 34 are fixed by U-shaped vertical lines 13 on the opposite side. In conclusion, the heat exchanger is fixed by the lower bridge portion 33 and the upper bridge portion 23 with respect to the left upper direction to the right lower direction. On the other hand, the heat exchanger is fixed by the bridge portions 23 and the claws 33 and 34 with respect to the right upper direction to the left lower direction. As a whole, the heat exchanger has a rigidity in any direction. The upper and lower bridge portions 23 and 33 are inserted alternately so that the U-shaped openings 11 and 12 are alternately blocked at the upper and lower portions.