According to this production method for a pre-filled syringe (100) and pre-filled syringe production device (10), a syringe assembly (107) having an outer barrel (106) filled with a drug solution (110) is held oriented with the barrel tip (102) at the bottom, the interior of the outer barrel (106) of the syringe assembly (107) is depressurized to a set pressure, and a basal end opening (104) of the outer barrel (106) is sealed with a gasket (112), whereby the gasket (112) is arranged at the sealing location, and the gasket (112) is pushed in towards the barrel tip (102) from the sealing location to an insertion location, at a speed faster than the speed in the gasket (112) would be moved utilizing atmospheric pressure.
