A medical injection device for supporting a medical container, the medical container comprising a barrel adapted to contain a composition and a needle extending from a distal end of the barrel, wherein the medical injection device comprises: a body configured to receive at least a part of the medical container, a plunger axially movable relative to the body along an axis of the body, needle cover movable relative to the body along the axis, the needle cover being configured to move successively between storage position wherein the needle cover covers the needle, an injection position wherein the needle cover exposes at least partially the needle, a safety position wherein the needle cover covers the needle and is prevented from moving back to the injection position.