Recently, current limiting molded case circuit breakers by which faults are ruptured rapidly and reliabiliy of power supply is raisen are widely used in large power distribution systems. It is necessary for the optimum design to analyze the repulsion forces on the contact systems in the circuit breakers. In this paper, the forces generated electromagnetically are obtained by 2-D and 3-D finite element method taking into account magnetic saturation of the iron yoke by which the repulsion forces are forced. And then, the differences between 2-D and 3-D finite element analysis are discussed. As the result of discussion, it is concluded that 3-D analysis can quantitatively calculate the repulsion forces in circuit breakers.