An electrical connector includes an insulative housing, a plurality of terminals retained in insulative housing, and a metal shell covering the insulative housing and including an inner side wall, a rear wall spaced from the inner side wall along a front-to-back direction, and an outer side wall bent forwardly from an outer side of the rear wall. The inner side wall defines an opening, and an inclined extensive plate extending forwardly and outwardly from an edge of the opening. The outer side wall has a retaining hole, and a front plate enclosing a front side of the retaining hole. The extensive plate has a hook bending inwardly and hitching the front plate after the hook passes through the retaining hole for preventing the outer side wall from moving forwardly and overly.