To provide a medicine administration device which is simple, easy to use, and able to prevent increase in pain and leakage of medicine when high viscosity medicine is infused.SOLUTION: A medicine administration device 10 includes: a body 12 having a medicine filling part 38 in which medicine is filled inside； an operation part 16 which is displaced by the operation of a user； and an extruder 30 which extrudes medicine inside the medicine filling part 38 into a needle tube 21 by traveling in the medicine filling part 38 based on the displacement of the operation part 16. Between the body 12 and the operation part 16, there is provided a restriction part (elastic member 35) which restricts displacement of the extruder 30 by the operation part 16, thereby restraining the travel speed of the extruder 30 and preventing increase in an internal pressure of the medicine filling part 38.SELECTED DRAWING: Figure 4【課題】簡便で使いやすく、高粘度の薬剤の注入時の痛みの増大や薬剤の漏れを防ぐことができる薬剤投与デバイスを提供する。【解決手段】内部に薬剤が充填される薬剤充填部３８を有する本体１２と、使用者の操作によって変位する操作部１６と、操作部１６の変位に基づいて薬剤充填部３８内を移動することにより薬剤充填部３８の内部の薬剤を針管２１に押し出す押し子３０とを備えた薬剤投与デバイス１０において、本体１２と操作部１６との間に操作部１６による押し子３０の変位を抑制する抑制部（弾性部材３５）を設けることで、押し子３０の移動速度を抑制させて薬剤充填部３８の内圧の上昇を防止する。【選択図】図４
