For geometric accuracy, the problem of tool deflection should be resolved for 2-D finish-cut contour machining. This paper investigates a path correction method for the nominal path given by the part program. The significance of the deflection error is first shown by experiments, and a direct compensation scheme is proposed that evaluates and corrects the tool path based on an instantaneous deflection force model until the desired contour is obtained in the presence of tool deflection in actual machining. The method is distinguished from the previous approach based on geometric and cutting simulation and on feed rate adjustment via adaptive control. Further, the method can be viewed as a direct and active method toward net-shape NC machining. Simulation results show the validity and adequacy of the path-modification scheme under various cutting conditions.