The present invention relates to a drug delivery device having a drive unit (5). The drive unit includes: a stator (7) including a plurality of coils (12) arranged continuously in the axial direction; and an armature (8) movable in the axial direction within the stator (7); The armature (8) includes a number of magnets (14) and pole pieces (15) that are continuously arranged in the axial direction. Each pole piece (15) is disposed between each adjacent magnet (14). At least one axial end of the armature (8) includes a termination pole piece (16).本発明は、駆動ユニット(5)を有する薬物送達デバイスに関する。該駆動ユニットは:軸方向に連続的に配置される複数のコイル(12)を含む固定子(7)と、固定子(7)内で軸方向に可動の電機子(8)とを含み、電機子(8)は、軸方向に連続的に配置されるいくつかの磁石(14)および磁極片(15)を含む。それぞれの磁極片(15)は、それぞれの隣接する磁石(14)間に配置される。電機子(8)の少なくとも1つの軸方向端は、終端磁極片(16)を含む。