To solve the problem wherein in a tapping apparatus using a bent tap, tapping process is carried out while applying a cutting process fluid to a nut processing part, and the nut after the tapping process with the cutting process fluid and chips attached thereto is discharged from the tapping apparatus, and the nut discharged from the tapping apparatus is subjected to drainage by a centrifugal separator and to chip removal by a screening device due to oscillation, and therefore, two steps: the drainage step and the chip removal step are required after the tapping process step.

In the tapping apparatus using a bent tap, the bent tap in which a midportion of a shank is curved is used, and a space is disposed at the midportion of the curved shank. The drainage of a nut and the chip removal are carried out simultaneously with tapping process by utilizing centrifugal force owing to the rotation of the bent part of the bent tap.