An injection device for injecting injection material, comprising:an elastic deformable element (3) able to exert a pushing force on a piston (20) of a syringe (2) so as to eject a quantity of injection material out of the syringe (2)a stopper (4) for retaining the extension of said spring (3) when the stopper is in a first position (A) and for releasing the extension of said elastic deformable element when the stopper is in a second position (B)an electric actuator (5) for moving the stopper (4) from its first position to its second position or from its second position to its first position.