Abstract: A device including an injection mold for the production of a boot from thermoplastic material, the boot having a boot shank of a color different from that of the shank flange and the outer sole, both of which have the same color, by molding the shank and then in a subsequent and simultaneous step, molding the upper shank flange and the outer sole onto the molded shank. The injection mold includes a last for fitting with a textile sock, a base stemple having a deadhead borehole for injection molding the outer sole, another base stemple having a deadhead borehole for molding the shank, and two sidepieces. The sidepieces having sliding elements and, in their closed position for molding the upper shank flange, accommodate at least one deadhead borehole which communicates with the deadhead borehole of the base stemple for the outer sole. The sliding elements cover the cavity for the upper shaft flange during the molding of the shaft and release it for the molding of the upper shank flange.