In order to represent geometrical relations between an object and its stereoscopic Rontgen image, a set of formulas were analytically derived in a previous paper. Recently, it has been found that the formulas may be reduced to the same form as lens formulas well-known in optics, setting up a pair of focuses in the stereoscopic Rontgen system. Hence, in each case, the formation of the stereoscopic Rontgen image can be favorably understood, corresponding to that of optical image by the lens. Besides, in the latter half part of the present paper, the close relation between the T_0-value and the relief of threedimensional Rontgen image in binocular vision is discussed in detail by use of the reduced formulas mentioned above.