This study used a two-dimensional finite element method to the preferred design for a cast circumferential clasp. Finite element models of the clasp arm with the constant flexibility were constructed, the stress was calculated, and the effects of taper and cross-sectional shape on stress were evaluated. The clasp arm with the taper of 0.8 showed less stress than those with other tapers, and the thinner and wider arms showed less stress than thosse with other cross-sectional dimensions. These results suggest that the use of the preformed clasp-pattern with a taper of 0.8 is preferable for reducing fatigue and/or permanent deformation of the clasp arm.