PURPOSE: To reduce an impact given to a wire by a method wherein a position of a tension rod immediately before the rod gives tension to the wire is detected and a braking voltage is applied to a tension motor to reduce the moving speed of the tension rod significantly.

CONSTITUTION: A tension rod 8 is slid outward and draws a wire 2 out. The wire 2 is wound on a toroidal core 1 automatically while a tension is given to the wire 2. A counter 18 counts the number LP of pulses corresponding to the amount of the shift of the tension rod 8. When a tension rod ascending instruction TC is put out, the counter 18 is cleared by a one-shot circuit 20 and starts the counting when a gate 17 is opened. When the tension rod 8, being ascended by a normal direction rotation of a tension motor 3, reaches the position where the braking is to be started, the count value LP of the counter 18 becomes identical to the number LBP of pulses. Therefore, an output of a comparator 19 changes from logic "0" to logic "1". According to this change, a timer 23 puts the logic "1" out for a predetermined period T. By this logic "1" , a gate circuit 22 is closed for the period T and a generator 15 of a voltage applied to the motor applies a braking voltage VB to the tennsion motor 3.