PURPOSE: To enable the wear of each surface plate to be automatically corrected by providing each correction carrier in a plane identical to a plane for each lapping carrier in the lapping machine wherein works held by each carrier are interposed between an upper and a lower surface plate while being relatively rotated so as to be lapped.

CONSTITUTION: When a sun gear 4 is driven by a drive means, and concurrently when a ring gear 5 is rotated via an interlocking mechanism, each carrier 3 meshed with both the gears 4 and 5 is revolved around the sun gear 4 while being rotated, and both the upper and lower surfaces of each work W held by holding holes 3a, are slid over the upper and lower surface plates so as to be lapped. Moreover, a plurality of correction carriers 7 are alternately disposed in parallel with each lapping carrier 3 between the upper and lower surface plates. Each correction carrier 7 is meshed with the sun gear 4 and the ring gear 5, however, each lapping carrier 3 is not allowed to be meshed therewith. This constitution thereby allows the wear rate (irregularities) of each surface plate to be corrected at all times, allows flatness to be kept up excellent for a long time, and also allows the lapping accuracy of the work to be enhanced.