A method for changing a mould of a moulding device, includes at least the following steps for dismounting a mould: (a) controlling fixing elements in order to release each mould half (20), (b) joining the mould halves together in order to form a single transportable sub-set, (c) opening mould carriers (14) from their closed position during steps (a) and (b) in order to extract, with a translational movement, the sub-set arranged in a reference position, and (d) removing the sub-set as a single unit from its reference position, from between the mould carriers.