To surely put surfaces of an optical element and an optical fiber together in alignment and to reduce elements of energy consumption.

One of optical element parts 2 and optical fiber parts 3 is set on a float 5 floating on liquid, and its front end face is butted against the front end of the other, and the direction of the front end face of the optical element parts 2 or the optical fiber parts 3 is finely adjusted under the action of buoyancy of the float 7 by this butting, and thus surfaces of both parts are put together so that a parallel contact state can be obtained.