The present invention relates to an ergonomic drive mechanism for a drug delivery device comprising:a housing (36),an axially displaceable piston rod (12) to act on a piston (18) of a cartridge (16) containing a medicinal product to be dispensed,an actuating member (26) operably engageable with the piston rod (12) and being slidably disposed relative to the housing (36) between a distal and a proximal stop position along a displacement path,wherein the actuating members displacement path is inclined with respect to the longitudinal extension of the piston rod (12).