The invention concerns a device (1) for measuring a fill level of a flexible medicine reservoir (6). The device (1) comprises a support (2) for supporting the flexible medicine reservoir (6) and a leaf spring member (3). A first section (31) of the leaf spring member (3) is mounted to a fixed bearing. A second section (32) of the leaf spring member (3) is guided by a floating bearing. The leaf spring member (3) is designed for contacting the flexible medicine reservoir (6) and for providing that changes in the fill level of the flexible medicine reservoir (6) effect changes of the form of the leaf spring member (3). A detector (5) is arranged for detecting the effected changes of the form of the leaf spring member (3) and for enabling measuring of the fill level of the flexible medicine reservoir (6).
