A chemical solution filling unit that can prevent the sealing performance of a seal member of a chemical solution storage unit from being deteriorated and can easily perform an operation of penetrating a needle tube with respect to the seal member of the chemical solution storage unit, A chemical filling set and a filling adapter are provided. A chemical solution filling unit 100 includes a chemical solution storage device 200 having a chemical solution storage section 230 for storing a chemical solution, a filling adapter 300 that is detachably attached to the chemical solution storage device, and a relative position of the filling adapter with respect to the chemical solution storage device. A lock mechanism 360 that restricts the movement of the adapter body, and the lock mechanism is configured so that the relative position of the adapter main body 310 with respect to the outer case 210 in a state where the filling adapter is mounted on the chemical solution storage device. Can be held at a non-penetrating position where the first needle tube does not penetrate the sealing member and a penetrating position where the first needle tube penetrates the sealing member. [Selection] Figure 8【課題】薬液貯蔵部のシール部材のシール性が低下するのを防止することができ、かつ、薬液貯蔵部のシール部材に対して針管を貫通させる作業を容易に行うことができる薬液充填ユニット、薬液充填セット、および充填アダプタを提供する。【解決手段】薬液充填ユニット１００は、薬液を貯蔵する薬液貯蔵部２３０を有する薬液貯蔵具２００と、薬液貯蔵具に脱着可能に装着される充填アダプタ３００と、薬液貯蔵具に対する充填アダプタの相対的な移動を規制するロック機構３６０と、を備えており、ロック機構は、充填アダプタが薬液貯蔵具に装着された状態で、外装ケース２１０に対するアダプタ本体部３１０の相対的な位置を、第１針管がシール部材を貫通しない非貫通位置と第１針管がシール部材を貫通する貫通位置とにおいて保持可能である。【選択図】図８
