Disclosed is a molding device for a machine for producing containers consisting of a thermoplastic material by forming a pre-heated preform using at least one pressurized fluid. The device includes: two mold carriers mounted in such a way that they can move in relation to each other about a rotational axis, between an open position and a closed position; two mold halves that each have a half-impression, are carried by a mold carrier, and are respectively mounted in the associated mold carrier; and fixing element that can dismountably fix each mold half, in its mounted position, to the mold carrier. The element for fixing each mold half to the mold carrier, which are mounted in such a way that they can move at least between a fixing position and a release position, can be controlled as they move between the positions when the mold carriers are in the closed position.