A syringe 10 includes a gasket 3, a barrel 2, and a plunger 4. The plunger 4 includes a helical rib 44 provided on an outer surface of a head portion 42, and the gasket comprises a helical valley portion 33 for threadedly engaging with the helical rib, a plunger-retaining annular rib 34, and an accommodation portion 32 for a part of the plunger at which the helical rib is formed. The annular rib 34 comprises a rib absent portion 35 for guiding, to the accommodation portion, the helical rib reaching the annular rib as threaded engagement is advanced between the plunger and the gasket. The helical rib comprises an entrance-restricting terminal end portion 46 for restricting the entrance of the helical rib into the rib absent portion, after the part of the plunger 4 at which the helical rib is formed is stored in the accommodation portion 32 of the gasket.
