To make it possible to supply a solid target substance in a normal state (room temperature, ordinary pressure (atmospheric pressure) condition) to a light emitting region (laser beam irradiation region) in a suitable density and size continuously or intermittently.

A light source device 1 by a laser generation plasma method is provided with a vacuum container 2 for forming a plasma emission room A in the inside, a laser beam irradiation equipment 3 for making a laser beam L condense to the laser beam irradiation position A1 in the vacuum container 2, a liquid target discharge nozzle 4 for carrying out discharge of the liquid target T to the laser beam irradiation position A1 in the vacuum container 2, a target recovery equipment 5 for recovering the liquid target T arriving after passing through the laser beam irradiation position A1 and which is arranged oppositely to the liquid target discharge nozzle 4 across the laser beam irradiation position A1, and the liquid target T constituted of the solution wherein the compound or the compound salt of the target substance is melted.