An injection device 110 is described having a housing 112 that receives a syringe 114 having a needle 118, wherein the syringe is supported in a syringe carrier 150. The injection device 110 has a removable cap 190. The syringe 114 and syringe carrier 150 are biased by a return spring 126 from an extended position in which the needle 118 extends from the housing 112 through an exit aperture 128 to a retracted position in which it does not. The syringe carrier 150 abuts a surface inside the removable cap 190 which prevents forward movement of the syringe carrier 150 when the cap is in place. The injection device is less prone to failure than prior art devices and is safer should failure occur.