To provide an electrodeless discharge lamp high in the efficiency of light emission.

A metal member 7, made of a nickel plate 7a and a support rod 7b, is arranged in the interior of an airtight container 5. On a surface of the nickel plate 7a, a secondary electron emitting film 7c containing a material which has a larger secondary electron emission coefficient than that of the nickel plate 7a and that of a phosphor in a phosphor film 11 is formed. As a result of this, in the lamp being lit, secondary electrons are emitted, when the electrons collide with the secondary electron emitting film 7c, and the number of electrons in the airtight container 5 is increased. That is, since lamp current is increased, lamp efficiency is improved.