To provide a metal vapor laser device that suppresses instability of initial electric discharge caused by a buffer gas for discharge in an electric- discharge tube, and instability of laser oscillation caused following it.

In a metal vapor laser, a vapor source metal 33 is held in an electric-discharge tube body 11, and a discharging buffer gas of a prescribed pressure is introduced, and initial electric discharge is generated by applying a voltage, and the vapor source metal is vaporized to be introduced into laser oscillation. In the metal vapor laser, a photoelectric conversion element 31 is placed in a condition where it can detect initial electric discharge light which exits from the electric-discharge tube main body generated by discharging buffer gas, and an initial electric discharge condition generated by the discharging buffer gas in the electric-discharge tube body is detected with the photoelectric transfer element, and the initial electric discharge condition is controlled with a feedback thereof.