PURPOSE: To provide the optical coupler which branches input light in an option polarization state to all output terminals with equal intensity without causing variation in branching ratio and also suppresses jitters of a signal due to propagation time differences of polarized light.

CONSTITUTION: A light signal which is inputted from an incidence-side optical fiber 51 is made incident on a propagation time equalization type optical path converting element 55-1 through a collimator array 52, the incident horizontal polarized light component and vertical polarized light component are made equal in propagation time to each other and branched to all the output terminals with equal intensity by polarized light distributing elements 53-1-53-6 and optical path converting elements 54-1 and 54-6 which are alternately arrayed and a propagation time equalization type optical path converting element 55-2, and signal light which is converged by a collimator array 56 is extracted and propagated to a projection-side optical fiber 57.