To enhance production capacity without bringing about the deterioration of a material yield in manufacturing a heat exchanger element.

The manufacturing method for the heat exchanger element comprises a manufacturing method for plates, wherein two plates are superimposed each other, and in a portion surrounded by the rand part formed on the opposed faces and jointed with each other, a coolant flows, the plate materials 37 made of strip metal is formed with a groove at the center in the lateral direction at a half slot roll forming process, then in a next roll forming process B, rand part forming and dimple forming, which is formed at the position wherein the coolant flows, are performed, and simultaneously the plates 37 are cut along the groove to obtain two plates in the lateral direction simultaneously.