A first optical base having a high-reflection mirror and a second optical base having a partial-reflection mirror are arranged in parallel to each other on both sides of an oscillator housing. A guide light source emits a guide light for aligning optical components in an optical path of a laser light emitted from an optical resonator and adjusting a processing point on a target object. An optical-component supporting unit includes optical components that guide the laser light in a direction perpendicular to an optical axis of the optical resonator. The guide light source is arranged on the second optical base.