An autoclave type sterilization device which includes an autoclave sterilization chamber with an electrical heating arrangement mounted thereon. This electrical heating arrangement employs one or more positive temperature coefficient (PTC) thermistors as heating elements. These heating elements are in direct thermal and electrical contact on opposing sides, which are coated with a conductive metal such as aluminum, with electrodes to supply electrical current. These electrodes are, in turn, in direct thermal contact on their outward-facing sides with respect to the heating elements with plates which are formed of a thermally conductive and electrically insulating ceramic material such as AL 2 O 3 , and the plates are in direct thermal contact on their outward-facing sides with respect to the heating elements with heat radiation units which include heat transfer portions which are fabricated to engage and are in direct thermal contact with a portion of the wall of the autoclave chamber. The heating elements are positioned by an electrically and thermally insulating frame made of heat-resistant material which serves, together with the heat radiation units, to fully enclose the heating elements. The heat radiation units further are in thermal and mechanical contact with each other which, together with the abovementioned enclosure of the heating elements, protects them from thermal gradients due to unbalanced heat transfer or exposure to air or gas flow and hence, from the known "pinch effect."