An injection device for administering or delivering fluid product, preferably a pen-shaped injection device, comprising - a housing , - a delivery device comprising a piston rod , which is movable relative to the housing in a delivery direction in order to dispense a set product dose, and a drive element , which is in engagement with the piston rod , - a dosing apparatus having a dosing sleeve and a rotary knob , - the rotary knob being rotated in one direction during the dosing process and in the opposite direction during the dose correction, - a dispensing button arranged coaxially on the dosing sleeve and - a receptacle for the product, the dosing apparatus being able to be coupled to the delivery device via a coupling mechanism, - the coupling mechanism consisting of at least two coupling surfaces (10b, 11 0b, 11f) each having a toothing consisting of teeth, and - the at least two coupling surfaces being able to be brought into engagement by means of a spring , - the coupling surfaces during the dosing process and during dose correction serving to generate an acoustic and/or tactile signal according to the set or corrected dose of the product to be administered, and - wherein the relative movement between the at least two coupling surfaces being able to be prevented by triggering the dispensing button , characterized in that - the coupling mechanism has a coupling member , which is arranged non-rotatable but axially displaceable on the drive element , - one of the at least two coupling surfaces is rigidly attached to the coupling member , and - a further one of the at least two coupling surfaces is rigidly attached to the dosing sleeve , so that the coupling surface (10b, 110b of the coupling member and the coupling surface of the dosing sleeve can be brought directly or indirectly into a coupling engagement with one another, a back drive safety being arranged between the housing and the drive element , so that the drive element can rotate only in the dispensing direction and a rotation of the drive element counter to the dispensing direction will be blocked. - a housing , - a delivery device comprising a piston rod , which is movable relative to the housing in a delivery direction in order to dispense a set product dose, and a drive element , which is in engagement with the piston rod , - a dosing apparatus having a dosing sleeve and a rotary knob , - the rotary knob being rotated in one direction during the dosing process and in the opposite direction during the dose correction, - a dispensing button arranged coaxially on the dosing sleeve and - a receptacle for the product, - the coupling mechanism consisting of at least two coupling surfaces (10b, 11 0b, 11f) each having a toothing consisting of teeth, and - the at least two coupling surfaces being able to be brought into engagement by means of a spring , - the coupling surfaces during the dosing process and during dose correction serving to generate an acoustic and/or tactile signal according to the set or corrected dose of the product to be administered, and - wherein the relative movement between the at least two coupling surfaces being able to be prevented by triggering the dispensing button , - the coupling mechanism has a coupling member , which is arranged non-rotatable but axially displaceable on the drive element , - one of the at least two coupling surfaces is rigidly attached to the coupling member , and - a further one of the at least two coupling surfaces is rigidly attached to the dosing sleeve , so that the coupling surface (10b, 110b of the coupling member and the coupling surface of the dosing sleeve can be brought directly or indirectly into a coupling engagement with one another, <EOS>