Abstract: Described herein is a flat lapping machine capable of precision-abrading simultaneously flat surfaces on the front and rear sides of a work in the fashion of lapping, polishing and grinding machines. The present invention contemplates to provide a flat lapping machine which is simplified in construction as compared with conventional flap lapping machines having a large number of carriers in planetary motions, and which can stop the respective carriers easily in specific positions and directions at the end of a lapping operation. To this end, the present invention employs a large number of support gear mechanisms each constituted by a plural number of small gears and located at uniform intervals around a center gear, rotatably supporting the respective carriers in predetermined positions while the respective carriers are driven by the center gear.