The liquid-administering instrument is provided with: a tube equipped with a main tube body that has an opening and with a sealing part for sealing the opening a gasket capable of sliding inside the main tube body a double-ended needle that is disposed on the front end side of the sealing part and has a front end needle tip and a back end needle tip a support member for supporting the double-ended needle so as to be movable between a separated position in which the back end needle tip is separated from the sealing part and a piercing position in which the back end needle tip pierces the sealing part and communicates with the tube interior an operation member for performing the operation of pressing the gasket toward the front end and discharging the liquid inside the main tube body from the double-ended needle and a cover capable of moving between a first position in which the front end needle tip of the double-ended needle is covered and a second position in which the front end needle tip is exposed. When the cover is in the first position, the double-ended needle is in the separated position and the sealing of the opening by the sealing part is maintained. When the cover moves from the first position to the second position, the double-ended needle moves in conjunction with said movement to the piercing position, thereby eliminating the sealing.Linstrument pour administration de liquide de linvention, est équipé : dun corps tubulaire à son tour équipé dun corps principal de corps tubulaire possédant une partie ouverture, et dune partie scellement qui scelle la partie ouverture dun joint pouvant coulisser à lintérieur du corps principal de corps tubulaire dune aiguille à deux pointes disposée côté extrémité avant de la partie scellement, et possédant une pointe daiguille côté extrémité avant et une pointe daiguille côté extrémité de base dun élément support destiné à un support tout en permettant un déplacement vers une position séparation où la pointe daiguille
