Abstract: A metal vapor laser device wherein the pressure of carrier gas within a metal vapor laser tube can be normally maintained constant and a stabilized laser beam can be generated. The metal vapor laser device comprises a metal vapor laser tube, and a carrier gas supplier for supplementing carrier gas into the metal vapor laser tube. The carrier gas supplier includes an outer tube substantially impermeable to the carrier gas, and an inner tube having a permeability to the carrier gas which varies according to temperature and partitioning the inside of the outer tube into a reservoir section and a tank section. The inner tube is disposed in the tank section of the outer tube in such a manner as to form a duplex tube. The carrier gas supplier further includes a heater provided on outer peripheries of regions of the outer tube including the reservoir section and the tank section.