PURPOSE: To obtain a heat exchanger capable of varying heat exchanger tube spans in order to comply with requirements by equally spacing penetration holes, which allow heat exchanger tubes to penetrate through, up and down on fins, allowing the fins to intersect the rows of the holes laid out and providing a raised area all over the whole width of the fins between the penetration holes.

CONSTITUTION: Fins 8 are made of a thin aluminum plate which is rectangular in shape. Penetration holes 9 with a cylinder-shaped raised edge 9a around each hole, are longitudinally bored at an equal span on the left side of the aluminum plate, thereby forming a row of holes A-A. There is installed a row of holes B-B on the right side at a symmetrical position to the center line Z-Z where the penetration holes 9, which belong to the row of B-B are positioned halfway between the penetration holes in the row A-A. There are installed raised areas 10 which are positioned between the penetration holes 9 and extend over the whole width of the fins 8, intersecting these rows of the penetration holes. Preferably, the cross sectional shape of the raised areas 10 be reverse V-shaped and they are slanted and intersected with the longitudinal direction of the fins 8. This construction makes it possible to install the heat exchanger tubes at a span suitable to the flow of air.