An electrical connector includes an insulating housing having a top wall (13), a bottom wall (19) and side walls (14) to define a receiving cavity (12) opening forward. The top wall (13) defines an opening (15) opened upward and forward. A pair of stopping portions (16) facing to each other being are formed on the top wall (13) and project into the opening (15), each of which includes a lead-in portion at a lower and rear corner thereof. A plurality of contacts (4) are assembled to the insulating housing, each of which includes a contacting portion (41) extending into the receiving cavity (12). A shell (2) is provided to shield the insulating housing (1). The lead-in portion of each stopping portion can provide facility operation during the mating process.