To process a pearl highly precisely by setting the structure of a sliding part of a body and a sliding part of a rotary table to a parallel groove type, and to prevent a piercing position of a pearl from being deviated by preventing the sliding operation from being rattled.

The structure of a sliding part of a body 4 and a sliding structure of a rotary table 2 are set to a parallel groove type, a presser plate 7 is provided, and a space is filled with lubricating oil. The material of a rotary table sliding piece 1 is set to bronze. A pin lowering guide plate 5 of the rotary table 2 is fitted in a recess of the body 4 and fixed by one of fitting screws 6. This constitution can improve the sliding accuracy between the body sliding part and the rotary table sliding part so as to improve the accuracy of the central hole piercing position of a pearl. The material of the rotary table sliding piece is set to the bronze and the surface processing is saved to reduce the cost. The pin lowering guide plate of the rotary table is set to a fixed type fixed by one of the fitting screws so that the assembling adjustment is eliminated to improve the production efficiency.