Medication delivery device, comprising: a tubular housing (11) having a proximal end and an opposite distal end； a drive (60) configured to exert force on a medication container (70) to expel the medication； and a drive holding part configured to releasably hold the drive in a prestressed state prior to the administration of the medicament, wherein the drive holding part (50) comprises a tubular extension part (52) for receiving the drive to be axially movable therein and a release ring (54) arranged coaxially in the tubular extension part, the release ring being axially movable between the proximal and distal positions along the outer surface of the extension part tubular, and in which the tubular extension part is configured to engage the drive when the release ring is in the proximal position and release the drive while the release ring moves distally leaving the proximal position, and characterized in that the ring release includes at least one pair of locking arms (55) extending in a di proximal retraction, said at least one pair of locking arms being configured to engage in a corresponding recess (58) formed on the outer surface of the tubular extension part when the release ring is in the proximal position.Dispositivo de administración de medicamento, que comprende: un alojamiento (11) tubular que tiene un extremo proximal y un extremo distal opuesto； un accionamiento (60) configurado para ejercer fuerza sobre un recipiente (70) de medicamento para expulsar el medicamento； y una pieza de sujeción del accionamiento configurada para sujetar de manera liberable el accionamiento en un estado pretensionado antes de la administración del medicamento, en el que la pieza (50) de sujeción del accionamiento comprende una parte (52) de extensión tubular para recibir el accionamiento para ser móvil axialmente en la misma y un anillo (54) de liberación dispuesto coaxialmente en la parte de extensión tubular, siendo el anillo de liberación móvil axialmente entre las posici
