A numerical method is proposed to obtain the individual stress intensity factor in a circular arc-shaped interfacial crack. The method is based on the path-independency of L integral and M(L) integral which involves two independent equilibrium fields, from which each stress intensity factor at the crack tip may be evaluated from the displacements and stresses remote from the crack tip. Some numerical examples are presented to compare the accuracy of this method to the well-known "method of extrapolation". It is found that the accurate values of each individual stress intensity factor k1 and k2 are obtained based on the present method without using the very fine meshes or singular elements at the crack tip.