A method of making a contact module of an electrical connector which includes a tongue and plural contacts exposed to two opposite surfaces of the tongue is characterized by the steps of: forming the contacts from a single contact carrier to have one contact thereof with a first contacting portion oriented reversely-symmetrically with respect to a second contacting portion of another contact thereof and to have two outermost contacts each with a respective integral latching portion; insert-molding the contacts with a first insulator while exposing front ends thereof and the latching portions; severing a carrier strip from the front ends of the plurality of contacts; and over-molding a second insulator to the first insulator and embedding the front ends of the plurality of contacts.