An injection unit for a shaping machine includes a plasticizing cylinder which has a collar and a carrier portion which has a trough. The plasticizing cylinder is arranged in the trough, and an axial movement of the plasticizing cylinder relative to the carrier portion is restrained in positively locking engagement by the collar bearing against the carrier portion. A clamping element which is fixed or shaped on the plasticizing cylinder is fixed by fixing elements to the carrier portion in such a way that the plasticizing cylinder is braced between the trough and the clamping element. The plasticizing cylinder is braced by bracing elements against lifting of the collar off the carrier portion in an axial direction of the plasticizing cylinder.