The blade behavior in the outer-blade slicing has been analyzed by computer simulation to clarify the machining mechanism. The main results obtained are as follows. (1) The blade deflection comes from a small lateral grinding force on the blade outer edge, and it is enlarged by the lateral grinding force on the blade side face. (2) The lateral grinding force on the blade side face takes the maximum value when the contact arc length between blade and workpiece tends to decrease in the machining process. (3) In the case that the blade was deflected in the machining process, the cutoff surface form obtained on the deflection side of the blade becomes concave and a large kerfloss occurs on this side. By contrast, the cutoff surface on the opposite side has a uniformly flat surface. (4) The values of lateral grinding force, blade deflection, waviness of cutoff surface and kerfloss increase with the asymmetric shape factor of blade, the speed ratio, the average tip angle of the grains on the blade side face and the inverse of blade thickness.