Patent ID: 7267163

Claim:
A heat exchanger comprising: a plurality of flat tubes laminated on each other, an external fluid flowing in a space formed between adjacent flat tubes; and fins interposed between the plurality of flat tubes, each of the fins being formed into a protruding and recessing shape having a flat plate portion joined to an outer wall face of the tube when it is viewed in a flow direction of the external fluid and a vertical plate portion crossing the flat plate portion, wherein heat is exchanged between the external fluid and an internal fluid flowing in the tubes, the flat plate portion includes a plurality of protruding portions arranged so that the protruding portions are inclined in the flow direction of the external fluid, protrusions of the protruding portions being increased toward a downstream side of the external fluid, the vertical plate portion meanders in the flow direction of the external fluid; a first protrusion which is located on a downstream side of a second protrusion in the flow direction of the external fluid has a height measured from the flat plate portion that is larger than a height of the second protrusion measured from the flat plate portion; and a connecting portion which connects the vertical plate portion with the flat plate portion meanders.