The present invention relates to a method for braze-welding a fixing plate and a flow channel cap in a heat exchanger, and to a heat exchanger produced by same. The method includes: providing a fixing plate 10 having a plurality of resilient protrusions 11 for snap-fitting; providing a flow channel cap 20, one end 22 of which is L-shaped to be snap-fitted onto the resilient protrusion 11 and the other end of which has a stepped portion 21; inserting the stepped portion 21 of the flow channel cap 20 into the resilient protrusion 11 such that an end 21b of the stepped portion 21 contacts an end of the resilient protrusion 11; pressing the L-shaped end 22 of the flow channel cap 20 against the resilient protrusion 11 of the fixing plate 10 such that the L-shaped end 22 is snap-fitted onto the resilient protrusion 11 and thus tightly contacts the fixing plate 10, and the resilient protrusion 11 thus press-contacts the end 21b of the stepped portion 21 to enable an end 21a of the stepped portion 21 to tightly contact the fixing plate 10; and braze-welding the fixing plate 10 and the flow channel cap 20. The above-described method eliminates a spot-welding process which might otherwise be performed prior to the process of braze-welding the fixing plate and the flow channel cap in conventional heat exchangers, to thereby reduce manufacturing costs and labor and to improve productivity.