An injection device comprises a barrel having a proximal end for a needle to protrude therefrom; a needle assembly having a double-pointed hollow needle and a biasing means operable to bias the double-pointed hollow needle away from the proximal end of the barrel; a cartridge; and a mechanism operable to cause the cartridge to be punctured by the first end of the needle, and to cause the second end of the needle to protrude from the proximal end of the barrel and to be locked in the protruded position.
