Disclosed is a multiple split optical waveguide in which a branch waveguide path at an output end of a branch part of a first stage defines an acute angle with respect to an input waveguide path, and a branch waveguide path at an input end of a branch part of an n-th stage is no more inclined toward a central axial line defined by an extension line of the input waveguide path than a branch waveguide path at an input end of a branch part of an (n+1)-th stage, n being an integer equal to or greater than two. Thus, the waveguide paths are prevented from spreading beyond the first branch angle, and it becomes easier to bring the outer waveguide guide paths back toward the center. This prevents an increase in the variations in length between the outer and inner waveguide paths.