An apparatus for introducing vaporized hydrogen peroxide at a concentration smaller than or equal to 10 PPM into an isolated chamber, and in particular into a chamber of a pharmaceutical isolator, the apparatus having: a vaporized hydrogen peroxide generator (13) operating through photocatalysis； a closed-path forced ventilation system (14) to introduce the vaporized hydrogen peroxide into the isolated chamber (2)； a spectroscopy gas analyser (15), which communicates with the isolated chamber (2) so as to measure the concentration of the vaporized hydrogen peroxide in the isolated chamber (2)； and a control unit (16) configured to control the vaporized hydrogen peroxide generator (13) as a function of measured values (CMeas) of the vaporized hydrogen peroxide concentration and of at least one reference value (CRef) of the vaporized hydrogen peroxide concentration.
