To provide an automatic polishing device capable of polishing not only a horizontal unpolished surface but also a vertical unpolished surface and a curved surface.

This automatic polishing device has a rotating abrasive material 11, arm 12 holding the abrasive material, support means 13 turnably holding the arm, angle adjusting means 16 supported to a mounting part 18 supporting one end to the arm 12 with the other end provided integrally with the support means 13, elastic means 19 energizing the arm 12 in a direction separating from the mounting part 18, and a track means 14 moving the support means 13. When a handle 16b of the angle adjusting means 16 is rotated, an angle of the arm 12 is changed, so that whatever angle unpolished surface may be polished. By providing the elastic means 19, the arm, at whatever angle may be, can apply a suitable polishing pressure to an unpolished surface 20.