A replaceable-needle inner needle base structure for use in a safe self-destructing syringe. A 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 a single-body integrated 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). The annular sealing stopper engaging part (4) is capable of forming a flexible cushioned engagement with the inner wall of a barrel body. An annular engaging-locking part (14) matching a plunger retracting piece is arranged in a cavity of the inner sleeve-type retracting-locking component (7). The needle base body deflects to a side after being retracted into the barrel body, while an injection needle therefore swings in the direction of a nearly 45 degree angle 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.La présente invention concerne une structure de base daiguille interne dotée daiguille interchangeable devant être utilisée dans une seringue à autodestruction sûre. Un corps de base daiguille a disposé en son sein un composant de verrouillage-rétraction de type à manchon intérieur (7). La partie supérieure du corps de base daiguille forme une partie de montage daiguille remplaçable (1). La partie inférieure du corps de base daiguille forme une partie de butée (2) étanche souple. La partie de montage d
