Disclosed are a solder and a solder paste used for soldering an electronic part to a circuit board. This solder comprises 2.0 to 3.5 wt % of Ag, 5 to 18 wt % of Bi and Sn for the rest. Alternatively, it further contains at least one element selected from the group consisting of 0.1 to 1.5 wt % of In, 0.1 to 0.7 wt % of Cu and 0.1 to 10 wt % of Zn.