To provide a structure of a polishing head whereby large pressing force can be applied, and the head can be freely tilted to follow tilting of a polishing surface.

A polishing head 12 of this polishing device is connected to a lower end part of a rotary driving drive shaft 15 through a pressing force transmitting ball 16, automatic aligning bearing 17, and a torque transmitting arm 18. An inner ring of the automatic aligning bearing 17 is fixed to a lower end part of the drive shaft 15, an outer ring of the automatic aligning bearing 17 is fixed to an upper surface of the polishing head 12. The pressing force transmitting ball 16 is inserted between a first spherical seat 31 provided on a rotary center shaft in a lower end surface of the drive shaft 15 and a second spherical seat 32 provided on a rotary center shaft in an upper surface of the polishing head 12. The center of tilting of the automatic aligning bearing 17 and the center of the first spherical seat 31 and the ball 16 are conformed to each other.