PROBLEM TO BE SOLVED: To provide a liquid medicine administration device capable of engaging easily and surely a disposable side power transmission part with a reusable side power transmission part, and suppressing adhesion of a foreign matter onto the reusable side power transmission part.SOLUTION: A reusable part 14 constituting a liquid medicine administration device 10 has a stopper part 80 for holding a cover part 76 in the open state against an energization power of an energization member 78 by being engaged with the cover part 76 for covering at least a part of a reusable side power transmission part 72. A disposable part 12 has an engagement release part 102 having a contact with the cover part 76, for releasing engagement between the cover part 76 and the stopper part 80, and maintaining the cover part 76 in the open state.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT
