Patent ID: 7866379

Claim:
A heat exchanger comprising: a first heat conduction plate and a second heat conduction plate both in substantially a square shape, each of the first and second heat conduction plates including: a plurality of substantially L-shaped air duct ribs forming a plurality of substantially L-shaped air ducts and heat conduction planes; a first outer peripheral rib for shielding leak of fluid flowing through the air ducts to an outside of the heat conduction plate; a second outer peripheral rib for shielding leak of fluid flowing through the air ducts to an outside of the heat conduction plate wherein a protrusion is formed into a hollow protrusion in the protruding direction of the air duct ribs is provided at an air duct end face side of the second outer peripheral rib, and the protrusion has a height greater than a height of the plurality of air duct ribs; and air-tightness ensuring means; wherein the first heat conduction plate and the second heat conduction plate are integrally molded of one sheet material, and are alternately laminated on top of each other.