PURPOSE: To stably manufacture a multi-layer printed wiring board of high reliability in which conduction established between wiring layers with no defective connection within via hole.

CONSTITUTION: Printed wiring boards 1 and 2 are laminated together so that connection land parts 13 and 23 correspond to each other, and a through hole 14 is filled with a solder paste 24. The solder paste 24 is printed on the printed wiring board 2 so that its apparent volume may exceeds that of the through hole 14. Then the laminated-body of the printed wiring boards 1 and 2 is heated and pressurized to melt the solder paste 24, so that conduction is established between circuit patterns 12 and 24, with the through hole 14 used as a via hole. At the same time, the printed wiring boards 1 and 2 are fused or made to become one body through fusion, for obtaining a multi-layer printed wiring board.