Moulding device (1) for moulding a container starting with a parison (3) in plastic material, comprising: two half-moulds (4a, 4b), which may be joined to define at least one housing cavity (5) for the parison (3); a blowing nozzle (6) applicable on the neck (3b) of the parison (3); a plasma generator (8) receiving a blowing fluid at a pressure higher than the atmospheric pressure and supplying plasma at a pressure higher than the atmospheric pressure to the blowing nozzle (6), so that the plasma is blown into the parison (3) placed in the housing cavity (5) to mould it and to decontaminate it.