Abstract: Sterilization apparatus, for medical instruments and similar objects, which is easy to handle and/or remove and which is mainly formed by a casing (1) provided with a sterilization boiler (11) and means for performing the sterilization process. The sterilization apparatus comprises a double-walled boiler (11) whereby fluid (13), such as demineralized water, which is present between the inner wall (3) and the outer wall (12), is heated by heating elements (17, 18) so as to achieve a sable temperature of the boiler wall as well as to generate steam (16). The apparatus further comprises a water reservoir (19), pump (21) and valve (22) for supplying water to the boiler and means (23, 24) for controlling the level of water, a valve (25) through which generated steam (16) can be injected into the sterilization chamber, a water-ejector (31) for drawing a vacuum in the chamber, and an aeration valve (29) for releasing the vacuum.