The present invention is related to a lid cover of a drug container, when performing aspiration of drug contained in an airtight drug container having a pierceable lid portion by using a syringe with a needle, the drug is prevented from leaking to the external space, which comprise a peripheral wall portion surrounding a pierceable face by the needle and a top face portion continuous with the upper portion of the peripheral wall portion. The peripheral wall portion and the top face portion are formed of elastic materials, while the peripheral wall portion is mounded to the lid portion, a closed space is formed between the pierceable face and the top surface portion to accommodate the pierceable face not to be exposed to the external space hermetically. The top face portion is opposite to the pierceable face and includes a central portion to be pierced by the needle, and a thin outer peripheral portion having a smaller thickness than that of the central portion.本發明係在使用具有針之注射器來吸引被氣密地保存於具有針可刺穿的蓋部之藥劑容器內的藥劑之際，用以防止藥劑漏洩至外部空間的藥劑容器之蓋外罩體，其具備：可安裝於蓋部的周壁部藉以圍住在蓋部中針可刺入的刺入面、以及與周壁部的上部連續且為針可刺穿的頂面部；周壁部及頂面部係由彈性材料所形成；在周壁部為被安裝於蓋部的狀態下，在刺入面與頂面部之間形成閉鎖空間，而且構成為依照不使得刺入面露出於外部空間的方式而氣密地保存刺入面；頂面部為與刺入面成相對向並具備：針可刺入的中央部、以及被形成在中央部的周圍且其厚度為比該中央部還薄的外周部。
