Abstract: A parallelepiped housing contains a displacement-transfer plate being slidable along the surface, and a pair of micrometer heads of the same shape and same size are mounted on a rear plate of said housing headed toward the front in said housing maintaining parallel and definite distance to one another.A differential lever is formed in such a length that the pivot parts at each tip of said pair of micrometer heads are rendered to serve as fulcrums, respectively, and a non-bisected part in the lengthwise direction of said lever is rotatably and pivotally supported as a point of application at the said displacement-transfer plate.A rectangular slider block is so constructed as to be guided along side plates and a base plate forming said housing, and is always pulled rearwards by a resilient means. Said slider block and said displacement-transfer plate are fastened via a determined space.Whereby coarse and fine adjustable displacements are realized at the displacement-transfer plate.