To provide a header of a tube-type heat exchanger of high quality and its manufacturing method capable of reducing working process and reducing manufacturing costs.

Three sheets of plate materials, that is, a header plate 1 and a header cover 3 as fastening members, and a resisting plate 2 as a fastened member having an engagement hole 9 are caulked by a pair of caulking brackets 4, 5 disposed on just upper and lower positions of the engagement hole 9, and having the projecting and recessed shapes inverse to each other, in a state of extruding the fastening members into the hole, thus the header for the heat exchanger can be manufactured.