A controller for a hybrid vehicle includes a slip controller which controls a lockup mechanism to slip in a set driving range, and an assist limiter which restricts assist of the motor generator in the range where slip occurs. Each member of a set is assigned a priority. Further, flatness of the surface of a dressing tool can be guaranteed because of sizing cutting-in; even if a thick grindstone of a few centimeters is used, the flatness can be maintained to the end; and processing with less in-face unevenness can be always carried out. The height of the wall is less than the overcoat thickness, forming a step.