An autoinjector device comprises a drive housing 10 and a syringe housing 12 which can be disconnected to allow insertion of a syringe. A drive mechanism in the drive housing is cocked by means of a cord 8 connected between the drive housing and the syringe housing. The drive mechanism comprises a drive gear 22 rotatably mounted in the drive housing and acting as a rotary crank connected by a connecting rod 26 to a plunger 28. In use the drive gear 22 is driven by a torsion spring 35 so that the drive mechanism extends the syringe from the syringe housing and expels a dose and then retracts the syringe back into the housing. A firing button 14 releases the drive gear to be driven by the torsion spring but is also engageable as a brake on the rim of the drive gear.
