A molding device for blow-molding or stretch-blow-molding containers from heated thermoplastic preforms, said device comprising at least one mold comprising at least two half-molds (1 a, 1 b) that can be moved with respect to each other between an open position in which they are parted from one another and a closed position in which they are firmly pressed against one another via collaborating respective bearing faces (2 a, 2 b) defining a parting line, locking means being provided to lock the two half-molds (1 a, 1 b) in the closed position, and comprising two lock elements (15, 16) mounted respectively on the two half-molds (1 a, 1 b) along the edges of the respective bearing faces, characterized in that: - the locking means extends substantially over the entire height of said half-molds, - each lock element (15, 16) comprises a multiplicity of hook-shaped projecting fingers (17, 18) distributed over the entire height of the lock element (15, 16) and which, on one lock element face away from the bearing face of the corresponding half-mold and, on the other lock element face toward the bearing face of the corresponding half-mold, said fingers (17, 18) of each lock element (15, 16) being substantially parallel and separated from one another by spacings (19, 20) the individual heights of which are slightly greater than the individual heights of the fingers (17, 18), - one of the lock elements being mounted fixedly on the corresponding half-mold (1 a) and the other lock element being mounted, on the other half-mold, such that it can move so that it can be slid parallel to the axis of the mold, - and actuating means functionally associated with said moving lock element in order to move the latter between two positions, namely: • a first position or unlocked position in which the fingers of the moving lock element are positioned respectively level with the spacings between the fingers of the fixed lock element, in which position the two half-molds are not locked together, and • a second position or locked position in which, with the two half-molds (1 a, 1 b) pressed firmly together in the closed position, the moving lock element is moved parallel to the axis of the mold so that its fingers engage respectively with the fingers of the fixed lock element, in which position the two half-molds are locked together in their closed position. - the locking means extends substantially over the entire height of said half-molds, - each lock element (15, 16) comprises a multiplicity of hook-shaped projecting fingers (17, 18) distributed over the entire height of the lock element (15, 16) and which, on one lock element face away from the bearing face of the corresponding half-mold and, on the other lock element face toward the bearing face of the corresponding half-mold, said fingers (17, 18) of each lock element (15, 16) being substantially parallel and separated from one another by spacings (19, 20) the individual heights of which are slightly greater than the individual heights of the fingers (17, 18), - one of the lock elements being mounted fixedly on the corresponding half-mold (1 a) and the other lock element being mounted, on the other half-mold, such that it can move so that it can be slid parallel to the axis of the mold, - and actuating means functionally associated with said moving lock element in order to move the latter between two positions, namely: • a first position or unlocked position in which the fingers of the moving lock element are positioned respectively level with the spacings between the fingers of the fixed lock element, in which position the two half-molds are not locked together, and • a second position or locked position in which, with the two half-molds (1 a, 1 b) pressed firmly together in the closed position, the moving lock element is moved parallel to the axis of the mold so that its fingers engage respectively with the fingers of the fixed lock element, in which position the two half-molds are locked together in their closed position. • a first position or unlocked position in which the fingers of the moving lock element are positioned respectively level with the spacings between the fingers of the fixed lock element, in which position the two half-molds are not locked together, and • a second position or locked position in which, with the two half-molds (1 a, 1 b) pressed firmly together in the closed position, the moving lock element is moved parallel to the axis of the mold so that its fingers engage respectively with the fingers of the fixed lock element, in which position the two half-molds are locked together in their closed position.