PURPOSE: To engage a torque converter and a drive plate with each other smootly and stably and to resolve a positional deviation completely by positioning directly the drive plate with a driving device.

CONSTITUTION: When a stopper 11 for the drive plate which is moved backward strats moving forward and a drive plate 5 approaches a point A or B of a position detector 21, the contact of a control mode changeover switch 15 is connected automatically to a contact (a) on the side of a speed voltage operator 16. The output of a power supply device 13 is given to a driving deivce 3, and it is rotated in a prescribed speed. When the drive plate 5 reaches the point B and the position detector 21 detects it, the contact of the control mode changeover switch 15 is switched automatically from the contact (a) to a contact (c), and the driving device 3 is driven by the output signal of a torque operator 18.