The injection device has a rotary case (2) with an engaging element (2a) that is engaged in the teething of a screw portion (3). An engaging element (1a) of a guide sleeve (1) is engaged in the teething of the screw portion. A dosing sleeve (4) is axial-movably arranged relative to the rotary case and relative to the guide sleeve. A screw thread (4b) of the dosing sleeve is engaged with the screw thread (2b) of the rotary case.