An electrical connector includes an insulative base, an insulative cover attached upon the base and moveable along a front-to-back direction, and an operation lever sandwiched between the base and the cover for moving the cover relative to the base in the front-to-back direction. The lever includes an actuating bar sandwiched between the upper head and the lower head, and an operation bar exposed outside of the base and the cover. The operation bar is rotatable between a horizontal position and a vertical position. The lower head includes a stopper around a front end of the operation bar with a locking section engaged with the operation bar wherein said locking section extends toward the operation bar either inwardly along the transverse direction or in the front-to-back direction.