Liquid injection tool 1, biological tow and having a tip opening 31 which is open at the distal end a contact member 3, and a hollow needle 24 having a sharp needle point 241, in a state where the living body contact member 3 is broken is addressed to the body surface, the needle tip 241 is located on the proximal side from the distal end opening 31 a first position which, the needle tip 241 and the inner structure 2 which is movably supported to the second position to puncture the living body surface to protrude to the front end side than the tip opening 31, the inner structure 2 I and a restriction member 6 which is detachably mounted. Restricting member 6, when the inner structure 2 is returned to the first position again moved to the second position from the first position, is fixed to the living body contact member 3 in the second position, It was separated from the inner structure 2, and remains in that position, to cover a portion near the tip opening 31.液体注入具1は、先端に開口する先端開口部31を有する生体当接部材3と、鋭利な針先241を有する中空針24とを備え、生体当接部材3が生体表面に宛がわれた状態で、針先241が先端開口部31よりも基端側に位置する第1の位置と、針先241が先端開口部31よりも先端側に突出して生体表面を穿刺する第2の位置とに移動可能に支持された内側構造体2と、内側構造体2に着脱自在に装着された規制部材6とを備えている。規制部材6は、内側構造体2が第1の位置から第2の位置に移動して再度第1の位置に戻る際に、第2の位置で生体当接部材3に対し固定されるとともに、内側構造体2から離脱して、その位置で留まり、先端開口部31付近の一部を覆う。
