To carry out soldering at comparatively low temperature by inserting only Sn as a solder alloy filler between metals to be jointed, rising the temperature of the jointed part to more than the melting temperature of the filler, and carrying out the liquid phase dispersion till the solder alloy filler phase in a metal component is vanished.

Sn is powdered, and a filler paste 10 with which a flux is kneaded, is applied on a jointed part of a printed base material 4, namely a metallic foil pattern 5. Then, a jointed part of an electronic part 6, namely a lead 7 is put on the metallic foil pattern 5, and a bottom part 9 of a press heating device 8 is put on the lead 7. The bottom part 9 is heated by a heating wire 11. Thereby, the filler paste 10 is fused for adhering the lead 7 on the metallic foil pattern 5. Furthermore, in a process that the filler paste 10 is fused, heated, and held, the pressure of 0.001-3.0 kg/mm2 is applied to the jointed part by the bottom part 9 of the press heating device 8.