A syringe 10 includes a gasket 3, a barrel 2, and a plunger 4. The plunger 4 includes a helical rib 44 provided at a head portion 42, and the gasket comprises a threaded engagement portion 33 being configured to threadedly engaged with the helical rib, a plunger-retaining annular rib 34, and an accommodation portion 32 for accommodating a part of the plunger at which the helical rib is formed. The annular rib 34 includes a rib absent portion 35 for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib 37 provided at a part on a proximal side of the retaining annular rib 34, and a part defined on a side of the distal end 36c of the helical projection 36, between a distal side annular rib 38 and a proximal side annular rib 39.
