Disclosed is a high power ultra-short pulsed laser device increasing pulse energy by using resonators. A pulsed laser device may comprise a first resonator making a pump beam resonate primarily and passing the pump beam which resonated through a first output mirror; and a second resonator comprising a first multiple reflection mirror and a second multiple reflection mirror. Also, the first multiple reflection mirror includes at least one first small area mirror, and the second multiple reflection mirror includes at least one second small area mirror, and the second resonator makes the laser beam delivered from the first resonator resonate by reflecting the laser beam repetitively. Therefore, the pulsed laser device may increase pulse energy without using a multi-stage amplifier so that a high power ultra-short pulsed laser beam can be generated.