An intraocular lens implantation injector has a base body and elongated actuation element projecting into a base body rear section and movably guided along an actuation axis. Actuation element movement is generated selectively by axial push actuation or by screw actuation about the axis. The actuation element features an external thread at least on one section. A switch element arranged on the base body is rotatable about the axis and has a passage, through which the actuation element extends. A spring arm arranged at the base body has an inner surface thread engagement structure facing the external thread. The passage features in inner surface having an inner radius varying at least in sections in a circumferential direction. A spring arm outer surface contacts the switch element inner surface. Switch element rotation generates spring arm elastic deformation towards/away from the axis, whereby the thread engagement structure is selectively engaged or disengaged.