Effects of thickness ratio of Fe-Sm and Fe-Tb films on magnetostriction, bending strain and its force driven by magnetic field were investigated for the mover device of three layered Fe-Sm/Si/Fe-Tb composite prepared by direct current magnetron sputtering process under the residual gas pressure of less than 4.0×10−4 Pa before argon sputtering and the sputtering pressure of argon gas (5N) of 2.0×10−1 Pa. Magnetostriction, bending strain and its force of the mover composites were strongly contributed by film thickness ratio of [Fe-Sm]/[(Fe-Sm)+(Fe-Tb)]. The high susceptibility with low bending strain was obtained for the device with the high film thickness ratio, whereas the high bending strain with low susceptibility was gotten for the device with the low thickness ratio.