PURPOSE: To obtain an operating device utilizing a non-stage adjusting type brake, and to always operate satisfactorily and surely by constituting a fixed regular circular brake drum, and a regular circular disk of a small diameter fitted loosely to an operating shaft, and also, provided in an eccentric state in the drum.

CONSTITUTION: When an operating dial 21 is rotated by a manual operation, and an operating shaft 19 is rotated counterclockwise, since the left/right width of an operating plate 33 is formed so as to be narrower than the left/right width of a fitting groove 36 of a regular circular disk 34, in the beginning, only the operating plate 33 runs idle, and an engaging projection 27 of the operating plate 33 abuts on a moving side engaging surface 48 of a right brake block 46. When the operating plate 33 rotates counterclock, since a clearance is formed between a lock projection 57 and lock side engaging surfaces 50, 51 of the left and the right brake blocks 46, 47, the clearance becomes a recess, and only the right brake block 46 is rotated counterclockwise without rotating an eccentric regular circular disk 34. Accordingly, a lock state of the right brake block 46 is released.