To easily adjust even when a friction surface of a lining in a brake and a clutch wears and the gap is required to readjust.

An adapter plate 34 equipped with a friction plate 35 for the clutch is installed in a pulley 31 rotatable for an output shaft 32. A friction plate 42 for the brake is installed in the input side of a securing part 41 housing an exciting coil 40. Adjusting mechanisms 50 and 60 for the clutch/brake for adjusting the position of the friction plate in the axial direction are installed at the part of the circumference side of the adapter plate and the securing part. Each adjusting mechanism has adjusting bolts B8 and B10 screwed into a screw hole formed in the friction plate through a through hole formed in the axial direction in the adapter or the securing part, and positioning bolts B9 and B11 screwed into the screw hole formed in the adapter plate or the securing part and brought into contact with the friction plate at the forward end. As a result, even when the friction surface of the lining in the brake and the clutch wears, and the gap is required to readjust, it can be easily adjusted and the maintenance becomes easy.