The compressed air gun (1) according to the invention comprises a body (2), comprising an upstream conduit (20b) that extends along a first axis (X20b) and a downstream air ejection conduit (20a), and a hole (22), which extends along a second axis (Y22), a closing member (16), which is translatable inside the hole between a closed position and an open position, a trigger (4) that can be manipulated between a released configuration, where it keeps the closing member in the closed position, and a blowing configuration, and means (8) for returning the trigger to its released configuration. This gun further comprises a tubular sleeve (14), which is immobilized inside the upstream conduit (20b), which extends parallel to the first axis (X20b) and which delimits an air passage, whereas the closing member (16), in the closed position, is suitable for closing off an air passage orifice by forming a sealed contact with the sleeve.