PURPOSE: To obtain an electric contact material which internally oxidized silver alloy by using, for contact material, such a substance as contains a specific amount of Sn, Mg and In to be solidly fused and that most of Sn is the intermetal compound with Mg.

CONSTITUTION: MgO is solidly fused into Ag as Mg2Sn, and In is added to make it have internal oxidation advancing function. In this case, In does not diffuse much in the entrance direction of O, and is internally oxidized at the present position, wherein construction and concentration change is extremely small from the surface layer to the central part, and it exhibits diffused construction of oxide fine particles of uniform quality. And the melting point of alloy is remarkably higher than Sn-In alloy and hardness at high temperature is high and fusing adhesion is weak. The metallic component to solidly fuse is in the range of 3W10weight% for Sn, 0.1W5weight% for Mg, and 0.5W6wetght% for In, and further Cd high in volatility at 720°C or thereabout is added by 0.1W5weight% so as to stabilize contact resistance at the time of fine current loads, or Fe is added by 0.01W0.5weight% so as to elevate forging effect.