Inside the fluid medicine is stored inside the receptacle which has capacity in axial direction as for the portable possible plunger head, when the fluid medicine exists within internal capacity of the aforementioned receptacle, being the 1st region which contacts with the fluid medicine, being the 2nd region which is located on the side which is opposite, to the internal capacity of the aforementioned receptacle of the 1st region and the aforementioned plunger head which include the 1st material adaptation to the fluid medicine within internal capacity of the aforementioned receptacle, in the plunger arm the 1st region of the joint possible 2nd region and the aforementioned plunger head and the 2nd regionThe 3rd region which is located between and, it includes, the aforementioned 1st region, the aforementioned 2nd region, and the aforementioned 3rd region at least one is produced with annular olefin copolymer and the material which includes one side of the annular olefin polymer.流体薬剤を収容する内部容積を持つ貯蔵容器内で軸方向に移動可能なプランジャヘッドは、流体薬剤が前記貯蔵容器の内部容積内に存在するときに、流体薬剤と接触する第1部位であって、前記貯蔵容器の内部容積内の流体薬剤に適合する第1材料を含む第1部位と、前記プランジャヘッドの、前記貯蔵容器の内部容積と反対の側に位置する第2部位であって、プランジャアームに接続可能な第2部位と、前記プランジャヘッドの第1部位と第2部位の間に位置する第3部位と、を含み、前記第1部位、前記第2部位、及び前記第3部位の少なくとも一つは、環状オレフィン共重合体及び環状オレフィン重合体の一方を含む材料で作製される。
