To prevent the breakage of the joint between a ceramic substrate and a glass epoxy substrate.The copper column is formed by a wiredrawing step for drawing a copper wire formed linearly to a predetermined diameter; a cutting step for cutting the copper wire, which has been drawn in the wire drawing step, in a predetermined length; a pressing step for pressing one end of the copper wire, which has been cut in the cutting step, in a longitudinal direction to form a copper column member; and an annealing step for annealing the copper column member, which has been formed in the pressing step, by maintaining a heating period of 60 minutes or longer at 600° C. or higher. Thereby, the Vickers hardness of the copper column becomes is 55 HV or less and the copper column is softened. Therefore, when joining the ceramic substrate and the glass epoxy substrate through the copper column, heat stress caused by a difference between the thermal expansion of the ceramic substrate and the thermal expansion of the glass epoxy substrate can be absorbed by the copper member. As a result, the breakage of the joint between the ceramic substrate and the glass epoxy substrate can be prevented.