Grinding force has a close relation to grinding inputs such as grinding wheel, work material, interference condition, grinding speed, grinding fluid and machine condition, and therefore varies widely with grinding inputs. On the other hand, grinding force affects significantly grinding outputs which are efficiency and quality evaluated with surface roughness, accuracy, surface integrity and so on. It is important to make clear the relations between grinding inputs and grinding force in order to control grinding outputs. In this paper, from the above point of view, the relations between grinding inputs and grinding force are experimentally investigated. It is pointed out that the normal grinding force, the tangential grinding force and its ratio are determined by the product of speed ratio of work speed to wheel speed and setting depth of cut as for interference conditions, and by the product of square of dressing feed and cutting depth of. dresser as for dressing conditions. Furthermore as for characteristics of work materials, the normal grinding force has a close relation to the yield stress, and the force ratio is related to the
elongation of work material.