An electrodeless discharge lamp is provided which prevents the problem of decrease in strength due to degradation of resin material, allowing secure fitting of a lamp part and a coupler member to a base even if it is used for a long time. A bulb containing a discharge gas and a coupler member for generating a high frequency electromagnetic field to excite the bulb are detachably fitted to each other via a base for fixing and supporting the bulb. The bulb and the base form a lamp part. The base comprises a base frame formed of a metal such as aluminum and a base cover formed e.g. of synthetic resin. The base frame has a coupler member fitting portion which is provided at a lower part thereof and fitted to the coupler member, wherein bulb fixing posts provided to stand on the coupler member fitting portion fix a bulb outer tube. Thus, the fitting portions of the lamp part and the coupler member to the base undergo less material degradation than a conventional one which uses a base of resin material.