A replaceable-needle inner needle base for use in a safe self-destructing syringe, comprising a needle base body. The needle base body has arranged therein an inner sleeve-type retracting-locking component (7). The upper part of the needle base body forms a replaceable-needle fitting part (1). The lower part of the needle base body forms a flexible sealing stopper part (2). The replaceable-needle fitting part (1) and the flexible sealing stopper part (2) are either a single-body integrated structure or a split-body assembled structure. An annular cushioning gap (3) is provided on the surface of the flexible sealing stopper part (2). The outer wall of the flexible sealing stopper part (2) outside the annular cushioning gap (3) forms an annular sealing stopper engaging part (4) that is capable of forming a flexible cushioned engagement with the inner wall of a barrel body. An engaging-locking part (14) matching a plunger retracting piece is arranged in a cavity of the inner sleeve-type retracting-locking component (7). When the engaging-locking part (14) and the plunger retracting piece are matched with each other, both retract the plunger, thereby retracting into the barrel body the needle base and deflecting same to a side, while an injection needle therefore swings towards a side of the inner wall of the barrel body and is locked by a neck part of the barrel body. This prevents the injection needle and the needle base from being pushed out of the neck part of the barrel body again, thus effectively preventing secondary injury caused by the needle being pushed out again.La présente invention concerne une base daiguille intérieure à aiguille remplaçable destinée à être utilisée dans une seringue à autodestruction sûre, comprenant un corps de base daiguille. Le corps de base daiguille est disposé en son sein dans un composant (7) de verrouillage-rétraction de type manchon intérieur. La partie supérieure du corps de base daiguille forme une partie de montage daiguille
