Abstract: An apparatus for adjusting the alignment of the optical fibers at a high precision, formed by a base frame having a plurality of pairs of V-grooves for mounting the optical fibers at mutually facing sides of the base frame, each V-groove being defined by a fixed member and a movable member, each movable member being movable within a guide groove defined between each adjacent fixed members, and one of each pair of V-grooves on one of the mutually facing sides has the fixed member and the movable member facing against the movable member and the fixed member, respectively, of another one of each pair of V-grooves on another one of the mutually facing sides; and a plurality of piezoelectric elements, each of which is connected with each movable member of each V-groove, for causing each movable member to move within the guide groove such that a displacement of each movable member makes an adjustment of a position of an optical fiber mounted on each V-groove.