Abstract: An apparatus for sterilizing containers such as bottles and vials for the pharmaceutical industry, in the form of a tunnel continuously traversed by a conveyor belt for said containers, comprising a sterlization chamber which utilizes a hot air stream in the laminar flow regime and is provided with air filters, characterized in that in said sterilization chamber the heated air is fed to a pressure chamber communicating in a sealed manner with said filters, and from these latter on to said containers to be sterilized, between said pressure chamber-filter system and walls of the sterilization chamber there being defined a jacket for recirculation of the air, in which the pressure is kept at a lower value than the pressure present in said pressure chamber-filter system.