An optical apparatus provided in an optical pickup includes first and second light sources, a light splitting element, a condensing lens, a mounting base, a light receiving element, and a protruding piece formed on the condensing lens. The condensing lens guides transmission light from the first light source or reflection light from the second light source that are split by the light splitting element to the light receiving element. By grasping the protruding piece to protrude in a direction perpendicular to a lens axis of the condensing lens, and adjusting a mounting position of the condensing lens on the mounting base, a sufficient amount of light for stable control of a light output is applied to the light receiving element for light output monitor.