PURPOSE: To aim at improvements in a lapped surface and a lapping speed, by installing a radial hole which is crossed with a concentrically circular groove in the circumferential direction of a lapping machine and pierces up to an outer circumference of the lapping machine, and making minute particles to be produced at the time of lapping so as to be washed away to the outside of the machine together with a abrasive solution.

CONSTITUTION: When a rotary shaft 3 rotates and a lapping machine 10 rotates due to rotation of this shaft, a work 5 rotates centering on another rotary shaft 4 by dint of frictional force with the lapping machine 10. At this time, the work 5 is lapped by friction with the lapping machine 10, and minute particles to be produced at lapping get into a groove 11, passing through four holes by dint of centrifugal force made by rotation of the lapping machine 10, and then these particles are discharged to the out side of the lapping machine 10. Thus, not only a lapping speed is improved but also a goos lapped surface is securable.