a finite element model of machining of frp has been developed for a better understanding of the microscopic machining mechanism such as deformation and fracture of both fiber (e glass) and matrix(polyester). the influence of the fiber direction angle and tool rake angle upon the mechanism is analyzed. the criteria of the maximum tensile stress and the modified equivalent plastic strain are assumed for fracture of the fiber and the matrix, respectively. the plastic deformation obtained is concentrated only in the matrix and the deformation mode changes with increase in fiber direction angle $theta$ : shear mode for $theta$ $equals$ 45 $degree$ , extrusion mode for $theta$ $equals$ 90 $degree$ and pulling up mode for $theta$ $equals$ 135 $degree$ . it is also found that the increase in $theta$ promotes the fiber fracture in deeper location from the cutting edge, thus deteriorating the surface finish on account of the overcut. the increase in rake angle decreases the extrusion of matrix and concentrates the deformation at cutting edge when $theta$ $equals$ 90 $degree$ . the fiber direction angle, however, exerts more marked influence upon the deformation than the rake angle. the analytical results mentioned above are also proven experimentally (edited author abstract) 4 refs. in japanese