PURPOSE: To manufacture an optical waveguide having mirror-faced end faces without cutting and polishing in the manufacture of the optical waveguide by using a spacer material having an internally blanked part and having a mirror-faced inside wall and an outside frame.

CONSTITUTION: A clad layer 6 is coated to a uniform thickness on a base plate 5 and the spacer 7 is placed thereon. A photosensitive resin havig about the same thickness is poured into the inside blanked part thereof. A film 8 and a mask 9 are placed on the photosensitive resin and are so positioned that the inside wall 7' of the spacer 7 is matched with the position at the incident and exit ends of the waveguide pattern of the mask 9. The mask 9, the film 8, the unexposed resin and the spacer 7 are removed after exposure. The outside frame 11 of which the inside surface in the inside blanked part is mirror-faced is installed in such as a way that the incident and exit end faces of the already formed optical waveguide contact with the inside wall of the frame 11. The clad layer is coated on the optical waveguide in the frame 11 and further a resin for embedding is poured thereon. The frame 11 is removed after the resin cures.