The mechanism magnifying displacements has beern widely used for fine positioning in such engineering field as semiconductor manufaeturing and STM. The mechanism introduced in this paper consists of elastic hinges and elastic lever. It is very important for designers how to obtain higher value of magnification factor, or the ratio of the output to the input in term of displacement. Due to elastic deformation of both the hinges and lever, engineers can not help estimating lower value of magnification factor than the ideal value. The ideal value can be determined on the assumption that the lever is rigid. In the second chapter, the authors state theoretically the displacement magnification efficiency on the secondary lever, and in the third chapter, they present the magnification efficiency of a complicated machanism, which comprises of a lot of elastic hinges, magnification lever and driving plate.