A laser device comprising: a solid-state laser medium which has oscillation wavelengths at a first wavelength and a second wavelength with higher light emission efficiency than at the first wavelength; an excitation section which excites the laser medium; a first resonator which is a resonator oscillating light having the first wavelength and has the laser medium on an internal optical path; a second resonator which is a resonator oscillating light having the second wavelength and has a common optical path which is an optical path in common for the first resonator including an optical path, on which the laser medium is disposed; a Q-value change unit (56, 57) which includes at least a Q-value change part and oscillates light having the first wavelength or light having the second wavelength through Q switching; and a control section which controls the excitation section and the Q-value change unit (56, 57), wherein the first resonator is constituted of a first mirror and a second mirror opposed to each other with the laser medium sandwiched therebetween, the second resonator is constituted of the first mirror and a third mirror opposed to the first mirror with the laser medium and the second mirror sandwiched therebetween, and the Q-value change unit (56, 57) is constituted of a first Q-value change section and a second Q-value change section, wherein that the control section controls the first Q-value change section and the second Q-value change section to oscillate light having the first wavelength through Q switching when a first delay time has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the first wavelength, the control section controls the first Q-value change section and the second Q-value change section to oscillate light having the second wavelength through Q switching when a second delay time, at which the intensity of light having the second wavelength is less than possible maximum intensity, has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the second wavelength, characterized by that the first Q-value change section is disposed on the common optical path and the second Q-value change section is disposed between the second mirror and the third mirror, and, the control section changes the set value of the first delay time or the second delay time according to the amount of excitation energy applied to the laser medium by the excitation section, wherein the first delay time and the second delay time are set to values such that the intensity of light having the first wavelength and the intensity of light having the second wavelength are equal to each other. a solid-state laser medium which has oscillation wavelengths at a first wavelength and a second wavelength with higher light emission efficiency than at the first wavelength; an excitation section which excites the laser medium; a first resonator which is a resonator oscillating light having the first wavelength and has the laser medium on an internal optical path; a second resonator which is a resonator oscillating light having the second wavelength and has a common optical path which is an optical path in common for the first resonator including an optical path, on which the laser medium is disposed; a Q-value change unit (56, 57) which includes at least a Q-value change part and oscillates light having the first wavelength or light having the second wavelength through Q switching; and a control section which controls the excitation section and the Q-value change unit (56, 57), wherein the first resonator is constituted of a first mirror and a second mirror opposed to each other with the laser medium sandwiched therebetween, the second resonator is constituted of the first mirror and a third mirror opposed to the first mirror with the laser medium and the second mirror sandwiched therebetween, and the Q-value change unit (56, 57) is constituted of a first Q-value change section and a second Q-value change section, wherein that the control section controls the first Q-value change section and the second Q-value change section to oscillate light having the first wavelength through Q switching when a first delay time has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the first wavelength, the control section controls the first Q-value change section and the second Q-value change section to oscillate light having the second wavelength through Q switching when a second delay time, at which the intensity of light having the second wavelength is less than possible maximum intensity, has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the second wavelength, the control section changes the set value of the first delay time or the second delay time according to the amount of excitation energy applied to the laser medium by the excitation section, wherein the first delay time and the second delay time are set to values such that the intensity of light having the first wavelength and the intensity of light having the second wavelength are equal to each other.