Liquid injection device 1 comprises a top member 3, a seal member 4 which is housed between the bottom member 2 and two. Bottom member includes a seal member peripheral portion pressing portion 22a formed by the upper surface of the annular wall 22, an annular edge portion 25 formed on the inner side of the periphery press portion. The seal member, the upper surface of the flange portion 42 by the upper member, the outer edge portion of the lower surface is pressed by the seal member peripheral portion pressing portion 22a, the inner edge of the lower surface, an annular edge portion 25 is pierced, the sealing member the skirt-like protrusion 43 of the reduction, the lower end outer peripheral surface of the bottom member in the insertion portion 41b is in close contact with the inner surface of the annular wall.薬液注入具1は、上部部材3と、底部部材2と両者間に収納されたシール部材4とを備える。底部部材は、環状壁部22の上面により形成されたシール部材周縁部押圧部22aと、この周縁部押圧部の内側に形成された環状エッジ部25を備える。シール部材は、フランジ部42の上面側が上部部材により、下面側の外縁部がシール部材周縁部押圧部22aにより押圧され、下面側の内縁部には、環状エッジ部25が刺入し、シール部材のスカート状突出部43が減少し、底部部材内挿入部41bの下端外周面が、環状壁部の内面に密着している。
