Disclosed is a method of controlling a laser apparatus, which has a laser light irradiation unit, an excitation unit including a flash lamp, a laser light shielding unit, and a control unit configured to control light shielding by the light shielding unit and release of the light shielding and control setting conditions of the flash lamp. The control unit performs a process of blocking the laser light by the light shielding unit when irradiation of the laser light is stopped, then performs a process of controlling the setting condition so that consumption of the flash lamp is reduced, performs, when the irradiation is restarted, a process of controlling the setting conditions so that the laser light is stably irradiated, and then performs a process of releasing the light shielding.