A heat exchanger is provided to easily manufacture a header pipe and combine a tube by limiting interval between a tube insertion hole of the header pipe and the tube and to improve durability by preventing cracks and leakage. A heat exchanger comprises plural tubes(120); a header pipe(110) formed with a tube insertion hole(111) to fit both ends of the tube and combined of one or plural members; a reinforcing member(115) jointed on the outer surface of the header pipe; a radiating fin(130) interposed between the tubes; and inlet and outlet pipes formed at the header pipe to inflow/discharge a heat-exchange medium. An interval(S) between the tube insertion hole and the tube is over 0.1 millimeter and under 2.5 millimeters to improve durability.
