In a optical head, a beam is emitted from a light emitting element in which a plurality of light sources are integrally formed, the light sources being able to emit beams having different wave lengths from one another. An optical system converges the beam coming from any one of the light sources onto an optical information storage medium. An optical separator separates a reflected beam coming from the optical information storage medium from the beam coming from the light source. A light receiving element detects light quantities of the reflected beam separated by the optical separator.