To provide a laser device in which the oscillation of a Q-switch is proactively used to improve pulsed laser light output, as well as to provide a photoacoustic measurement device provided with said laser device. A laser device (1) that emits a pulsed laser light by radiating an excitation light onto a laser medium (51) while a first voltage is applied to a Q-switch (57), then after the radiationof the excitation light, changing the voltage applied to the Q-switch (57) from the first voltage to a second voltage, wherein the timing of the start of application of the first voltage during normaloperation is set to a time when the intensity of the pulsed laser light reaches a maximum, the intensity cyclically changing due to the oscillation of the Q-switch (57).