A syringe comprising: a cylindrically-shaped gasket comprising a closed distal end, an open proximal end, and an inner cavity portion extending distally from a proximal side; a barrel comprising a distal opening portion, the barrel configured to slidably accommodate the gasket; and a plunger comprising a head portion configured to be accommodated in the inner cavity portion of the gasket and a helical rib disposed on an outer surface of the head portion, wherein the gasket comprises, on an inner surface of the inner cavity portion, a helical projection forming a threaded engagement portion configured to be threadedly engaged with the helical rib of the plunger, and a plunger retaining annular rib positioned on a distal side near the helical projection, wherein the inner cavity portion comprises an accommodation portion positioned distally from the plunger retaining annular rib, the accommodation portion configured to accommodate a part of the head portion of the plunger at which the helical rib is formed, and wherein the plunger retaining annular rib comprises a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the retaining annular rib as threaded engagement is advanced between the plunger and the gasket and, wherein the gasket comprises, on an outer peripheral surface, a distal side annular rib having an outer diameter larger than an inner diameter of the barrel, a proximal side annular rib having an outer diameter larger than the inner diameter of the barrel, characterized by an intermediate annular rib disposed between the distal side annular rib and the proximal side annular rib and at a part of the gasket defined on a side of the plunger retaining annular rib, wherein an outer diameter of the intermediate annular rib is smaller than the outer diameter of the distal side annular rib and the outer diameter of the proximal side annular rib. a cylindrically-shaped gasket comprising a closed distal end, an open proximal end, and an inner cavity portion extending distally from a proximal side; a barrel comprising a distal opening portion, the barrel configured to slidably accommodate the gasket; and a plunger comprising a head portion configured to be accommodated in the inner cavity portion of the gasket and a helical rib disposed on an outer surface of the head portion, wherein the gasket comprises, on an inner surface of the inner cavity portion, a helical projection forming a threaded engagement portion configured to be threadedly engaged with the helical rib of the plunger, and a plunger retaining annular rib positioned on a distal side near the helical projection, wherein the inner cavity portion comprises an accommodation portion positioned distally from the plunger retaining annular rib, the accommodation portion configured to accommodate a part of the head portion of the plunger at which the helical rib is formed, and wherein the plunger retaining annular rib comprises a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the retaining annular rib as threaded engagement is advanced between the plunger and the gasket and, wherein the gasket comprises, on an outer peripheral surface, a distal side annular rib having an outer diameter larger than an inner diameter of the barrel, a proximal side annular rib having an outer diameter larger than the inner diameter of the barrel, characterized by an intermediate annular rib disposed between the distal side annular rib and the proximal side annular rib and at a part of the gasket defined on a side of the plunger retaining annular rib, wherein an outer diameter of the intermediate annular rib is smaller than the outer diameter of the distal side annular rib and the outer diameter of the proximal side annular rib.