Abstract: A wafer arrangement pitch altering apparatus comprising a pair of cylindrical grooved cams parallelly disposed, a plurality of cylindrical grooves formed to intersect a given generatrix of the grooved cams with respectively equal pitches, disposed symmetrically each other around the peripheral surfaces of the cylindrical grooved cams, and intersections of the generatrix and the cylindrical grooved cams are moved at mutually dissimilar desired proportions along the axes of the cylindrical grooved cams in consequence of its rotation, plural pairs of moving elements disposed between the cylindrical grooved cams facing each other and provided with pins fitting into the cylindrical grooves on the corresponding cylindrical grooved cams, a pair of means for retaining the moving elements in a manner movable only in the axial direction of the cylindrical grooved cams, a cylindrical grooved cam driving element for rotating the cylindrical grooved cams by a prescribed angle in the mutually opposite directions, main groo