Medicament injection apparatus, it include: main body, the main-body structure is at reception drug cartridge, the drug cartridge is sealed with transparent spacer, needle holder, the needle holder keep needle, needle sleeve, the needle sleeve is arranged to be axially moveable relative to the main body around at least part of the needle holder and needle arrangement And retaining device, the retaining device are connected to the needle holder and are connected to the needle sleeve, and can move relative to the main body along the main shaft of described device Wherein the retaining device is connected to the needle holder, so that when the needle sleeve and the retaining device shift one section of preset distance towards the proximal end of the main body, the needle holder and needle are shifted axially towards the proximal end of the main body, and are detached from from the retaining device And wherein the needle sleeve is configured to: in the needle sleeve when the axial displacement in the proximal direction is more than the preset distance, the needle sleeve is detached from from the needle holder.
