Abstract: An automatic injection device, including a housing arranged along a longitudinal axis and having a forward end and a rearward end, the housing is configured to receive a syringe including at least one syringe piston and a needle coupled to a forward end thereof; a plunger rod adapted to be retained with respect to the housing in an initial operative orientation; at least one resilient element arranged to forwardly bias the plunger rod relative to the syringe; a needle shield adapted for selectable axial displacement with respect to the housing along the longitudinal axis, whereas rearward displacement of the needle shield exposes the needle and forward displacement of the needle shield covers the needle; and a trigger element configured to be axially rearwardly displaced upon rearward displacement of the needle shield relative to the housing and thereby allow forward displacement of the plunger rod relative to the syringe under the urge of the at least one resilient element.