A hermetic electrical adaptor includes an insulative housing and a plurality of contacts retained therein. The housing includes a base having opposite first and second surface in a vertical direction, and a set of first side walls extending from the first surface to form a first mating cavity. Each contact includes a retention section extending through the base, a first extending section located in the first mating cavity and including a first bending section. The set of first side walls forms, adjacent to the first surface, a first recess communicating with the first mating cavity so as to expose a portion of the first extending section in the first recess. A waterproof glue occupies the first recess and a bottom portion of the first mating cavity so as to surround the exposed portions of the first extending sections of the contact for assuring sealing of the adaptor.