PURPOSE: To eliminate polarization and to obtain unpolarized light by pressing the 1st part of an optical fiber against the center of a single-mode optical fiber, and then pressing the 2nd part adjoining to the 1st part against the center from at 45° to the 1st part.

CONSTITUTION: Force 4 is applied to the 1st part 11 toward the center of the optical fiber 1. Namely, the force applied to the 1st part 11 is perpendicular to a top surface 21. Force 5 is applied to the 2nd part toward the center of the optical fiber. The force 4 and force 5 contains 45° and the force 5 applied to the 2nd part 12 is perpendicular to the top surface 31. When linear polarized light such as a semiconductor laser output is made incident from an end part 13 of the optical fiber 1, unpolarized light is projected from the other end part 14.