TIGHTENING TOOL AND PREDETERMINED WORK DETECTING UNIT

PROBLEM TO BE SOLVED: To provide a tightening tool which can recognize whether or not a worker has tightened all bolts of a predetermined number and a predetermined work detecting unit which can be attached to and detached from the tightening tool.SOLUTION: A tightening operation detecting unit 50 is provided at the lower end of a handle housing 12 and fixed at the handle housing 12 with a screw 52. By loosening the screw 52, the tightening operation detecting unit 50 can be removed from the handle housing 12 as shown in Fig.6. The tightening operation detecting unit 50 has a unit control section (operation section) 61, a vibration sensor (vibration detection) 62 and a sensitivity operation circuit 63, and can determine whether or not vibration detected by the vibration sensor (vibration detection) 62 is peculiar vibration which is generated while the tightening tool 1 keeps on performing tightening operation by detecting a frequency of the vibration.