The invention relates to a sterilization apparatus (10) and to a method for the sterilization of an object (7) by a gaseous or liquid fluid comprising: a sterilization chamber (8) in which the object (7) is positioned, at least an acceleration device (2) for accelerating the fluid to a predetermined flow-speed, at least a filter device (3) for separating particles from the fluid, characterized in that the sterilization apparatus further comprises at least an orifice device (4) providing a plurality of openings, and a control apparatus for determining the flow-speed of the fluid on the basis of a pressure difference (&Dgr;p).