Provided are a laser device and an optical apparatus including the same. The laser device includes a pump light source configured to provide pump light, a gain medium configured to acquire a gain of seed laser light by using the pump light, a first curved mirror and a second curved mirror, which are provided at both sides of the gain medium to reflect the seed laser light into the gain medium, an output mirror configured to transmit a portion of the seed laser light reflected by the second curved mirror and reflect the other portion of the seed laser light to the gain medium, a first acoustic wave generator connected to the gain medium and configured to provide a first photoacoustic wave in the gain medium, and a second acoustic wave generator connected to the gain medium and configured to provide a second photoacoustic wave in the gain medium.