The invention relates to a fixed actuator in a round window niche, comprising a sleeve, a fixing support device and a telescoping device. The front end of the sleeve is provided with a circumferentialpartition plate and the rear end is provided with a clamping table. The fixing support device comprises an expansion sleeve and a position fixing nut arranged on the outer side of the sleeve, whereinthe position fixing nut is screwed with the sleeve through a screw pair, one end of the expansion sleeve abuts against a partition plate located at the front end of the sleeve, and the other end abuts against the position fixing nut; The telescopic device comprises a position adjusting bolt, a telescopic device and an excitation film arranged on the inside of the sleeve. The invention also relates to a fixing device for the fixed actuator in a round window niche, including a box, a first knob, a second knob, a clamping arm, a tightening wheel, a rotating shaft, feet and a reduction gear set,andbeing used for fixing the actuator at the round window niche of the use object, thereby solving the problems of the existing round window excitation actuator, such as the implantation difficulty, the small support rigidity, the unstable support and the uncontrollable initial pressure, and can be widely applied to the technical field of hearing aid equipment.