To improve the treating capacity by raising the stability of a work by slanting a support face for a shaft body head part to be formed on a rotary table by several degrees in a direction wherein a position is raised on an outer peripheral face of the table.

Notch grooves 3 are provided at a specific pitch on the outer periphery of a rotary table 1, and the head part of a work A is fitted thereto. The work A is fed from a linear feeder arranged on the outer periphery of the rotary table 1. For the work A fitted to the notch groove 3, the head part is supported by a support face 2. Then, it is introduced in a fixed guide provided on the outer periphery of the table by rotation of the table 1, and inspection whether good or bad is executed while it advances along an inner periphery of the fixed guide. For this selector, selectors by a long or short-measuring sensor, a sensor for measuring whether plating is good or bad, and a sensor for measuring whether a screw thread is good or bad, are provided midway on a work transfer passage, the work A wherein inferiority judgment is executed by measurement with respective sensors is discharged to a bad product discharge opening, and good product is discharged to good product discharge opening.