FIELD : medicine.SUBSTANCE : invention refers to medical equipment, namely to an elongated body of an injection device for delivering a liquid medicinal agent. Body comprises : tubular cartridge holder (20) for accommodating drug-filled cartridge (50), and having near connecting end (21); body (30) for arrangement of drive mechanism (5), during operation of cartridge (50) engaged with piston (52), where body (30) has distal connecting end (31) adapted to be connected to near connecting end (21); where one of connecting ends - near (21) or far (31) - comprises inserted part (22), where the other of connecting ends - near (21) or far (31) - comprises receiver (32) for receiving insert part (21) in longitudinal direction; where inserted part (22) comprises at least one fastening element (25) for forced engagement with fastening element (35) of corresponding strap on receptacle (32) in order to provide longitudinal interlocking (6) of cartridge holder (20) and body (30); where fastening elements (25, 35) of inserted part (22) and receiver (32) comprise at least one pair of radial projections (135) joining radial recess (125) made on inner wall (36) of receiver (32) and on inserted part (22) outer wall (26); and where inserted part (22) is retained from movement in axial direction by flange section radially outward (23); where radial depth (D) of radial recess (125) is less than thickness of side wall of inserted part (22) or thickness of sidewall (33) of receiver (32); where side wall (33) of receiver (32) comprises chamfered longitudinal end surface (34) corresponding to shape of skewed surface of thrust (24) of flange section (23).EFFECT : disclosed is a body for an injection device and a mutual connection of body parts.13 cl, 8 dwg