The injection syringe is intended to be disposed of after one use and comprises a syringe barrel (1), a barrel stopper (12) that can be moved in the syringe barrel (1) by a piston rod (11), and a needle assembly (25) received in the syringe barrel (1). The piston rod (11) and the needle assembly (25) can be connected to one another by coupling means (20, 40) in order to draw the needle assembly (25) back into the syringe barrel (1) after injection has been completed. According to the invention, the needle assembly (25) comprises a plastic needle holder (26) which encloses a stainless steel injection needle (27) along part of its length and which, in relation to the interior of the syringe barrel (1) receiving an injection solution (50), is sealed off by a sealing insert (36) of pharmaceutical rubber through which the rear end of the injection needle (27) protrudes. By these measures, an injection solution (50) present in the injection syringe is in contact exclusively with permitted materials, and the syringe can therefore be stored in a pre-filled state.