In a laser device which uses a laser medium having two oscillation wavelengths with different light emission efficiencies and a photoacoustic measurement device including the laser device, the intensity of light at each wavelength made independently controllable without increasing the number of parts of the device. The laser device includes a laser medium (laser rod 51) 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 (flash lamp 52), a first resonator C1, a second resonator C2, a Q-value change unit (56 and 57) which oscillates light having the first or second wavelength through Q switching, and a control section (control circuit 62) which controls the excitation section and the Q-value change unit. The control section oscillates 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, and oscillates light having the second wavelength through Q switching when a second delay time has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the second wavelength.
