A syringe helical guiding mechanism, comprising a bidirectional helical guiding barrel assembly (50), a helical connection ring (60), a unidirectional ratchet (70), a helical plunger (80), and an injection plunger assembly (90). The bidirectional helical guiding barrel assembly (50) comprises an outer helical guiding barrel (51) and an inner helical guiding barrel (52) threadedly connected with and disposed inside of the outer helical guiding barrel (51). The helical connection ring (60) is assembled in the outer helical guiding barrel (51). The unidirectional ratchet (70) is assembled in a unidirectional ratchet grove (524) of the inner helical guiding barrel (52). The helical plunger (80) is disposed inside of the bidirectional helical guiding barrel assembly (50) and is threadedly connected with and disposed inside of the helical connection ring (60). The injection plunger (91) of the injection plunger assembly (90) penetrates the unidirectional ratchet (70) and axially slidably penetrates the helical plunger (80). When the mechanism is applied to a syringe, by utilizing the cooperation between the large pitch stroke combined structure of the bidirectional helical guiding barrel assembly (50) and the small pitch stroke combined structure of a screw connector and the helical plunger (80), the helical guiding mechanism can convert an axial pressing force on the injection plunger assembly (90) into a rotational force, and converts a large stroke rotational force into a small stroke rotation force for injection, thereby achieving the goal of set-amount dosage injection using a simple and force-conserving operation mode.Linvention concerne un mécanisme de guidage hélicoïdal pour seringue, comprenant un ensemble cylindre de guidage hélicoïdal bidirectionnel (50), une bague de raccordement hélicoïdale (60), un cliquet unidirectionnel (70), un piston hélicoïdal (80) et un ensemble piston dinjection (90). Lensemble cylindre de guidage hélicoïdal bidirectionnel (50) compre
