The present invention is a silver alloy suitable for use in a probe pin made of an Au-Cu alloy, wherein the silver alloy comprises 30 to 50% by weight of Cu and Ag as balance. This silver alloy further comprises 2 to 10% by weight of Ni to further improve strength. A probe pin made of these materials has stable contact resistance even under low contact pressure. The probe pin has excellent strength and antifouling property to adhesion of a foreign matter from a contact object due to repetitive use. Thereby, the probe pin usable in a stable manner for a long period of time can be obtained.