An
injection device including a housing for containing a
syringe having a bore extending from an end surface, a needle communicating with the bore through the end surface and a dispensing
piston movable in said bore towards said end surface so as to expel the contents of the
syringe through the needle, the housing having an opening at one end through which the needle may extend, a resilient member for biassing the
syringe and the needle inwardly off the housing, a first
coupling element moveable towards said one end so as to move the needle of the syringe out of the opening and to move the dispensing
piston of the syringe towards the end surface, a mechanism operable to release the syringe such that the needle moves inwardly off the housing, a drive
coupling for extending from said first
coupling element to the dispensing
piston of the syringe so as to transfer movement of said first coupling element to the dispensing piston wherein the mechanism is triggered to release the syringe and includes components to
delay release of the syringe until a predetermined period after being triggered such that it can be ensured that the dispensing piston reaches the end surface before the syringe is released and / or the mechanism includes an
inertial mass moveable with the first coupling element and drive coupling and a release member actuable by the
inertial mass to release the syringe such that when the dispensing piston releases the end surface of the syringe and the first coupling element and drive coupling stop moving, the
inertial mass continues to move so as to actuate the release member to release the syringe.