PURPOSE: To make possible accurate correction of a lapping surface plate and highly precised polishing of a workpiece.

CONSTITUTION: In a lapping surface plate, which is provided with a carrier 20 making rotations and also revolutions by engaging with and interposing between a solar gear 16 and an internal gear 18 which are respectively rotatable in the identical direction, and which is made by pressing a workpiece supported by the carrier 20 with the upper and lower rotatable lapping surface plates 12, 14, angular velocity of the solar gear 16 is larger than that of the internal gear 18 and a changeover means for changing the angular velocity of the solar gear 16 to a plurality of steps under this condition, is provided. A converter for rotating velocity of the solar gear 16 and the internal gear 18, of which angular velocity of the internal gear 18 is larger than that of the solar gear 16, and which is provided with a changeover means for rotating velocity of the solar gear 16 and the internal gear 18 under this condition, is also provided.