The present invention is a silver alloy including silver as the main component and at least one rare-earth element as a first dopant element, and excellent in reflectance maintenance property. In the present invention, the first dopant element is preferably samarium, neodymium, lanthanum, cerium, ytterbium, terbium, dysprosium, holmium, erbium, thulium, europium, and gadolinium. Also, in the present invention, the silver alloy preferably includes, as a second dopant element, at least one element selected from copper, manganese, silicon, chromium, nickel, cobalt, yttrium, iron, scandium, zirconium, niobium, molybdenum, tantalum, tungsten, platinum, gold, rhodium, iridium, palladium, indium, tin, lead, aluminum, calcium, gallium, bismuth, antimony, strontium, hafnium, and germanium.