The limit of applicability of the former published method for an embedded cack in a finite body is investigated by comparing with the conventional stress intensity factor formula. The error of estimated stress intensity factors by published slice synthesis methodology increases for a decreasing distance of the crack tip from the back surface of the body. The reason is considered that the former published slice synthesis methodology conform the crack opening behavior of an embedded crack obtained analytical solution in an infinite cracked body to the ones obtained by the slice synthesis methodology. The improved slice synthesis methodology to increase accuracy of stress intensity factor solutions in a finite body is proposed by incorporating a correction coefficient into the formulation. The validity of improved slice synthesis methodology is confirmed by comparing the stress intensity factor solutions with ones by finite element analyses.