PURPOSE: To improve a reliability of connections by pushing an annealed copper sphere in the through hole of a double side printed wiring board from one or both surface sides of the board and by electrically connecting wiring patterns being on both the surfaces of the board with each other, pressing the annealed copper sphere.

CONSTITUTION: An annealed copper sphere 14 is pushed in a through hole 13 being in a wiring board 11, and it being pressed from both the surface sides of the board 11, the annealed copper is made to contact with the wall surface of the through hole 13 and the surfaces of both wiring patterns 12. Consequently, the surfaces of the patterns 12 are interconnected electrically. In the state in which the electrically highly conductive annealed copper sphere 14 having the larger volume than the one of the through hole 13 of the wiring board keeps being pushed in the hole 13 by a jig 15, the annealed copper sphere 14 is pushed in the hole 13 simultaneously from under the board 11 by a jig 16 too, and then, is leveled with the surfaces of both the wiring patterns 12 respectively. Thereby, the double side printed wiring board which has a high reliability for connections even when temperature being changed can be obtained by the simple method.