PURPOSE: To contrive to lower than manufacturing cost and as well as improve productivity of the heat exchanger by a method wherein a cooling plate member is formed by winding a refrigerant tube within a plane so as to bring into contact one tube with another at its side.

CONSTITUTION: The metallic refrigerant tube 1 having a circular section and the predetermined length is, at first, bent rectangularly from its end and, after that, the remaining part is wound along the outer peripheral side of the rectangularly wound part with a plurality of turns. Henceforth, the wound tube is pressed down to the state that adjacent refrigerant tubes 1 come into tightly contact with each other by flattening the section of the refrigerant tube 1. Consequently, a cooling plate member 2 or a heat exchanger of rectangular and flat plate shape as a whole, is bonded by means of, for example, bonding agent onto a pair of supporting beams 3 placed in parallel so as to keep a fixed form in order to make up a cooler 4.