A substance delivery device (autoinjector) for use with a container (120) (such as a syringe) containing the substance comprises: a body arranged to house or hold the container a plunger (140) which is movable with respect to at least a portion of the body, the plunger being arranged to act upon the container so as to move the container with respect to said portion of the body wherein the plunger is also arranged to expel at least a portion of the substance from the container and wherein the device comprises means for priming the container.
