To provide an optical fiber positioning mechanism suitable for an optical fiber movable switch and an optical cross connect switch which uses this and has excellent scalability.

Since inclined surfaces 7 and 8 formed on optical fiber supporting bodies 2 and 3 are tilted toward only one axial direction of an X-axis and a Y-axis, as the order of moving, the member 2 (movable in the Y-axis direction, here) the moving direction of which is orthogonal with the direction of the inclined surface 7 is moved first. When moving the member 3 after that, the surfaces 7 and 8 come into contact with each other to be more effective than the contact of edge parts. After starting the contact of the inclined surfaces with each other, the optical fiber supporting bodies continue moving until they come into contact with the sidewalls 5 and 6 of each other. When tension by wires 16 and 17 is added finally to be standstill, matching of the axial centers of an optical fiber is finished. In addition, the rotation axis of a motor is fixed in this state to keep optical connection.