Abstract: The balloon inflation device comprises a syringe (2) having a syringe barrel (4) and a syringe piston (6) slidably and rotatably movable. The piston (6) has an exterior threading. The syringe barrel also comprises a retractable mechanism (30) for retaining the piston (6) in the syringe barrel, which mechanism (30) is switchable between a retracted state in which the piston (6) is free to slide in the syringe barrel and an active state in which the free sliding of the piston (6) is impossible and in which the piston (6) can be screwed or unscrewed. The device comprises a pressure gauge (104) for measuring the output pressure of the syringe barrel (4). The pressure gauge (104) is mounted angularly movable with respect to the syringe barrel (4) and around the axis of the syringe barrel (4).