To secure a small-size and inexpensive cable drum braking device, capable of braking the rotation of a cable drum according to looseness in a cable.

A drum receiving shaft 3 is draggably supported on a cable drum 1, while both the ends are supported on two jacks 4 free of rotation. A pair of brake arms 23 are attached to both first and second plates 20 and 34 installed in the jacks 4 rotatably around two brake arm mounting shafts 24, and a cable guide shaft 35 is installed in space between both the tip parts. In addition, a brake disc 32 is locked to an end part of the drum receiving shaft 3, and the circumferential part is situated in space between a pair of shoes 22a of a disc brake 22. In this connection, an operating lever 26 of a hydraulic tank 25 driving the disc brake 22 and the brake arms 23 are connected together via a rope 27.