The optical connector has the plug for holding the plurality of optical fibers arranged in parallel in a left-right direction, and the receptacle and the board for holding the plurality of optical waveguides arranged in parallel in a left-right direction. The plug has the lower surface located along a direction the plurality of optical fibers arranged. The receptacle has, at the part which projects toward a side of the first holding member, the bottom surface which faces the lower surface and positions the lower surface, when butting joint the plurality of optical fibers and the plurality of optical waveguides. Further, a space which is located between the lower surface and the bottom surface is located below the plurality of optical fibers.