Abstract: An actuating device comprising a bracket and an operating device is provided. The front end portion of the operating device is provided with an anchoring portion and a first operating portion. The first operating portion defines a first, a second and a third edge which are connected with each other. The bracket is provided with a first post which passes through the receiving chamber. The operating device can be moved such that the first operating portion is contacted with the first post. Wherein when the operating device is moved upward, a temporary braking function is effected; and when the operating device is moved downward, a continuous braking function is effected.