Patent ID: 7490661

Claim:
A heat exchanger comprising: a plurality of tubes which are stacked; and a header tank defining therein a circulation portion in which fluid flows, the header tank extending in a stacking direction of the tubes, wherein: the header tank is connected with a longitudinal-direction end of each of the tubes so that the circulation portion communicates with interiors of the tubes, the circulation portion being partitioned into an inlet side passage and at least one other passage; and the header tank has an inflow port member which is arranged at a longitudinal-direction end of the inlet side passage and provided with a single center mainstream opening defining a mainstream flow to a central portion of the circulation portion of the header tank and a substream opening defining a substream flow of fluid introduced toward the tubes, the single center mainstream opening and the substream opening being the only openings in the inflow member, the entire substream opening being located further from the longitudinal-direction end of each of the tubes than the single center mainstream opening.