FIBER COUPLING DEVICE

PROBLEM TO BE SOLVED: To sufficiently prevent small core displacement of two adjusted lenses 23, 29 when fixing an X-axis slide 45 to a Z-axis slide 35.SOLUTION: A lock screw 103 for pressing a lock piece 99 toward an XY plane of a Z-axis slide 35 is provided with the XY plane of the Z-axis slide 35 by being screwed into the XY plane, the lock screw 103 is inserted into a through hole 99h of the lock piece 99 relatively displaceably in a Y-axis direction and in an X-axis direction, and when the lock piece 99 is pressed toward the XY plane of the Z-axis slide 35 by a turning operation of the lock screw 103, the lock piece 99 is flexibly deformed with a groove 99s side as an original point only as much as clearance C in a Z-axis direction to come into press-contact with the XY plane of the Z-axis slide 35.