A laser light source apparatus comprises a laser light source that emits laser light; a prism with one optical flat face, through which the laser light from the laser light source passes, that is perpendicular to an optical path of the laser light; and a vibration driving device that vibrates the prism to move the prism parallel to a direction in which an optical path length of the laser light in the prism changes, along a flat face located in the other optical flat face that does not intersect perpendicularly with the optical path of the laser light in the prism.