A plasma emission device in an embodiment includes: an electromagnetic wave generator; a waveguide transmitting an electromagnetic wave emitted from the electromagnetic wave generator, an antenna receiving the electromagnetic wave transmitted through the waveguide; an electromagnetic wave focuser which is irradiated with the electromagnetic wave from the antenna; and an electrodeless bulb disposed in the electromagnetic wave focuser. A light-emitting material filled in the electrodeless bulb is excited by the electromagnetic wave focused by the electromagnetic wave focuser to perform plasma emission. The electromagnetic wave generator includes a cathode part and an anode part. A maximum output efficiency of the electromagnetic wave to be generated with an input power of 700 W or less is 70% or more.