To drastically reduce lead content causing to reduce the environmental contamination and to obtain a solder having the same performance as the tin- lead eutectic solder in the soldered temp. and the solder-joined parts by using a low lead-containing solder containing specified quantities of Pb, Bi, Ag, Cu, In and Sn.

The low lead-containing solder contained by wt.% of 5.8-20 Pb, 0-10 Bi, 0-3.5 Ag, 0-2 Cu, 0-10 In and the balance Sn is used. It is desirable to make the low lead-containing solder paste by mixing the low lead-containing solder particles and flux. The metal and the flux are kneaded to make the low lead-containing solder paste so that the metallic composition after melting becomes the low lead-containing solder composition. Bi and In have the effect for lowering the m.p. but in the case of being too much content, this solder becomes brittle and the performance is lowered. Ag improves the strength and Cu improves the wettability but in the case of being too much content, the m.p. thereof becomes high.