TAPPING DEVICE

PURPOSE:To prevent a tap tool from being damaged and tapped screw threads from being damaged by calculating a reasonable stopping position of the tap tool from set position data regulating the relationship between a set rotational position and a set feed position previously set in a control unit on the basis of a detected stopping position. CONSTITUTION:An emergency stopping position detecting means 4 detects, for example, an output signal Q1-2 of a rotational position sensor 13 at an emergency stopping end point B as a rotation stopping position of a tap tool 6 by an emergency stopping signal Q3-3 outputted from a control unit 3, and outputs the quantity of electricity which corresponds to a detected rotational position, as a detected rotation stopping position Q4. A position correcting means 5 extracts set position data D from a memory 30 of the control unit 3 by means of the detected rotation stopping position Q4 outputted from the emergency stopping position detecting means 4, and calculates a reasonable, for example, feed stopping position C of the emergency stopped tap tool 6 from the extracted set position data D on the basis of the detected rotation stopping position Q4.