An illumination apparatus for single-base lamps is equipped with a power receiving plug which receives a supply of power by being fitted into a base socket of a power supply side, a main body which forms an integrated body with said power receiving plug, and a plurality of base sockets arranged on said main body on the opposite surface with said power receiving plug, wherein said base sockets are mounted at slopping angles which spread outward with respect to the axis of said power receiving plug.