A position-control stage system is disclosed, which is enhanced in prolusion to turn a turntable relatively to a bed through a bearing and also improved in operating performances including high-speed traveling and high response, even with made as small as allowed in diametral dimension. To this end, a motor includes a primary side having armature windings lying on a circular flat surface of a first retainer member secured to the bed, and a secondary side having a field magnet secured on the turntable. The bearing has an outer race held in place with combination of the bed and the first retainer member, and an inner race held in place with combination of the turntable and a second retainer member.
