A heat exchanger manufacturing method for manufacturing a heat exchanger by brazing of multiple heat transfer pipes, multiple fins, and headers, the heat exchanger including, the multiple fins arranged in a thickness direction, the multiple heat transfer pipes joined to each fin with the heat transfer pipes each being inserted into cutout recessed portions as cutouts of side portions of the fins on one side, and the headers each joined to both end portions of each heat transfer pipe to couple the multiple heat transfer pipes and having internal spaces for collecting or distributing fluid flowing in the multiple heat transfer pipes, the method comprising: a first step of assembling the heat transfer pipes, the fins, and the headers to form an assembled member and setting such that a protruding length Tf of a protruding portion of each fin from a corresponding one of the heat transfer pipes and a distance Th from each heat transfer pipe to an outer surface of a corresponding one of the headers on the same side as the protruding portion are substantially equal to each other; a second step of placing, after the first step, the assembled member on a conveyer with the protruding length Tf side and the distance Th side facing down; and a third step of conveying, after the second step, the assembled member into a furnace by the conveyer to heat the assembled member, thereby performing brazing of the assembled member. the multiple fins arranged in a thickness direction, the multiple heat transfer pipes joined to each fin with the heat transfer pipes each being inserted into cutout recessed portions as cutouts of side portions of the fins on one side, and the headers each joined to both end portions of each heat transfer pipe to couple the multiple heat transfer pipes and having internal spaces for collecting or distributing fluid flowing in the multiple heat transfer pipes, the method comprising: a first step of assembling the heat transfer pipes, the fins, and the headers to form an assembled member and setting such that a protruding length Tf of a protruding portion of each fin from a corresponding one of the heat transfer pipes and a distance Th from each heat transfer pipe to an outer surface of a corresponding one of the headers on the same side as the protruding portion are substantially equal to each other; a second step of placing, after the first step, the assembled member on a conveyer with the protruding length Tf side and the distance Th side facing down; and a third step of conveying, after the second step, the assembled member into a furnace by the conveyer to heat the assembled member, thereby performing brazing of the assembled member. a first step of assembling the heat transfer pipes, the fins, and the headers to form an assembled member and setting such that a protruding length Tf of a protruding portion of each fin from a corresponding one of the heat transfer pipes and a distance Th from each heat transfer pipe to an outer surface of a corresponding one of the headers on the same side as the protruding portion are substantially equal to each other; a second step of placing, after the first step, the assembled member on a conveyer with the protruding length Tf side and the distance Th side facing down; and a third step of conveying, after the second step, the assembled member into a furnace by the conveyer to heat the assembled member, thereby performing brazing of the assembled member.