Heat exchanger

A heat exchanger comprising:

• a plurality of flat tubes disposed in a plurality of tiers, each of the flat tubes including a planar portion facing vertically;
• and
• at least one fin disposed in a wavily folded state in a ventilation space interposed between a pair of the flat tubes disposed on two vertically adjacent tiers, the fin including
• a heat transfer portion having a folded portion joined to the planar portion of each of the pair of flat tubes, and
• a cut-and-raised portion protruded from the ventilation space, the cut-and-raised portion being formed by raising a periphery of a cutting line segment when a material of the fin is wavily folded, the cutting line segment being set in a vicinity of a center line lying on an apex of the folded portion before the material of the fin is wavily folded,
• the cutting line segment being formed by
• a combination of cutting line segments intersecting with the center line or
• a combination of a cutting line segment intersecting with the center line and a cutting line segment displaced with respect to the center line,
• the combination of cutting line segments being disposed latterly adjacent to the flat tube and being asymmetrical relative the center line of the folded portion prior to being folded such that adjacent cut and raised parts on opposite sides of the center line have different outer peripheral shapes as viewed along the heat transfer tube adjacent thereto.