A lead-free solder alloy comprises 1.0-5.0 wt % Ag, 0.01-0.5 wt % Ni, one or both of (a) 0.001-0.05 wt % Co and (b) at least one of P, Ge, and Ga in a total amount of 0.001-0.05 wt %, and a remainder of Sn. The solder can form solder bumps which have a high bonding strength and which do not undergo yellowing after soldering.