The invention relates to a hearing instrument, comprising an audio signal source (28), an audio signal processing unit (34) for processing the audio signals provided by the audio signal source, and implantable stimulation assembly (18) for stimulating a round window (24) or an oval window of a patient according to the processed audio signals, wherein the stimulation assembly comprises an electromechanical actuator (20) for vibrating an output member (62, 162) according to the processed audio signals, a support member (72) to be fixed at the patients skull, and a lever element (22) having a proximal end portion (66), a distal end portion (64) and an intermediate portion (68) connecting the proximal end portion and the distal end portion, wherein the actuator is fixed at the support member, wherein the intermediate portion is supported by the support member in manner enabling a pivoting motion of the lever element, wherein the output member is arranged for imparting an pivoting motion to the lever element by acting on the proximal portion, and wherein the distal end portion arranged is for acting on the round or oval window in order to make the membrane (24) of the round or oval window vibrate according to the pivoting motion of the lever element.Cette invention concerne un instrument daudition comprenant une source de signaux audio (28), une unité de traitement des signaux audio (34) qui traite les signaux audio émis par la source de signaux audio, et un ensemble de stimulation implantable (18) qui stimule la fenêtre ronde (24) ou la fenêtre ovale du patient en fonction des signaux audio traités. Lensemble de stimulation comprend un organe de commande électromécanique (20) qui fait vibrer un organe de sortie (62, 162) en fonction des signaux audio traités, un support (72) fixé au crâne du patient, et un levier (22) doté dune partie dextrémité proximale (66), dune partie dextrémité distale (64) et dune partie intermédiaire (68) reliant la partie dextrémité proximale e
