To surely prevent insufficient fastening of machine screws by comparing a set part number value with a count value for a setting completion signal by a counting means to be equal or not, so that information can be given by an information means.

When members 30, 35 are fastened with machine screws BS1-BS3, if the machine screw BS1 is threaded by an electric torque driver 10, an incomplete setting signal and setting completion signal are generated in a comparator for a counting means by a signal generating means to judge setting completion. A counter is used for count value analog-conversion and a part number set value is input to a comparing means to be compared with a count value for the setting completion signal. At the time when the settings of the machine screws BS1-BS3 are completed, a sound source 20 is operated via a reset means to inform user thereof. After a preset delay time elapsed, a count value for the counter is reset. The preset number of parts is shown in a display column 18a in a display means 18 and a value counted by the counter is shown in a display column 18b.