A general computer program for the design and analysis of machine tool structures by the use of the finite element method has been completed. The system consists of three parts; the input program for the automatic mesh generation in idealizing the structure, the program for the analysis of the static, dynamic and thermal deformations of the machine tool and an output program to draw the configuration of these deformations and to print out the numerical data requested. A sample computation is carried out on the thermal deformation of a jig grinding machine in the steady and non-steady state as well as in the on—off operation of the machine.