In a method of making a guide wire 1 by using a heat mold device 1, the metallic mold body 2 is made from the material, the thermal expansional coefficient of which is the same of a metallic coiled wire 91 to stabilize a shape-forming configuration 94. A plurality of the mold bodies 2 are arranged in a mold frame 6A to make the reverse side 22 of one mold body 2 tightly contact with the obverse side 21 of other mold body 2 among the neighboring mold bodies 2. A jig arm 7A sandwiches an array of metallic mold bodies 2 and the side plate 63 to serve as a securement member 7. Upon manufacturing the guide wire 9 for use in the medical field, the method of making the heat mold device 1 contributes to producing a high quality guide wire with a high productivity.