The liquid administration device 10 has a bottom at the distal end and an opening at the proximal end, and has a cylindrical body that can be filled with liquid and a sharp needle tip at the distal end of the cylindrical body. And a structure having a needle tube whose base end can communicate with the inside of the cylindrical body, a gasket installed in the cylindrical body and capable of sliding along the axial direction of the cylindrical body, and pressing the gasket An operation member that has a pusher, moves the pusher in the distal direction, and performs a push operation for discharging the liquid from the needle tube, and a push that generates a push force that pushes the gasket through the pusher A mechanism, and a pressing force transmission blocking unit that blocks the pressing force from being transmitted to the gasket during the pressing operation.液体投与具１０は、先端部に底部、基端部に開口部を有し、内部に液体を充填可能な筒体と、該筒体の先端部に位置し、先端に鋭利な針先を有し、基端が前記筒体の内部と連通可能な針管と、前記筒体内に設置され、前記筒体の軸方向に沿って摺動し得るガスケットとを備える構造体と、前記ガスケットを押圧する押し子を有し、該押し子を先端方向に移動して、前記液体を前記針管から吐出させる押圧操作を行なう操作部材と、前記押し子を介して前記ガスケットを押圧する押圧力を発生する押圧機構と、前記押圧操作の途中で、前記押圧力が前記ガスケットに伝達されるのを阻止する押圧力伝達阻止部とを備える。
