A pulse laser includes a laser medium, a charge storage unit, a power source unit configured to supply an electrical charge to the charge storage unit, an excitation unit configured to cause irradiation of the laser medium with excitation light onto the laser medium by being supplied the electrical charge stored in the charge storage unit, a switching unit configured to repeatedly supply the charge stored in the charge storage unit to the excitation unit, an energy monitoring unit configured to monitor energy stored in the charge storage unit, and a control unit configured to prevent the switching unit from supplying the electrical charge stored in the charge storage unit to the excitation unit when the energy monitored by the energy monitoring unit is larger than a threshold.
