To define the tip of a scaler to polish an object in a desired angle, by defining a guide means into a desired inclination angle by an angle defining means and moving a polishing means along the guide means.

A knob 33a and a stopper 35 of a protractor 31 erected on the plate surface 5a of a surface plate 5 are operated to release fixation of a bar member (guide means) 21 to align an index to the scale of the protractor. Next, the bar member 21 is fixed again by the knob 33a and the stopper 35. The bar member 21 in that condition is inserted through a long hole 6a of a base plate 6 to place the base plate 6 on the surface plate 5 before a polishing member is movably attached to the bar member 21. Further, a hand rest 71 is laid on the base plate 6. A confirming means is laid on the upper face of the edge of the scaler 9, a hand holding the scaler 9 is supported by the upper end 71a of the hand rest 71 and an object is polished by first and second grinders of the polishing means 4 in that order. Thus the object can be polished in a desired angle.