An electrical connector comprises an insulating housing defining a receiving room with a front mating opening and a plurality passageways extending rearwards, a plurality of contacts retained in the passageways, and a first spacer member retained in the insulating housing and sustaining said contacts upwardly. Each contact comprises a holding beam with tabs formed thereon and a holding leg downwardly extending from a rear end of the holding beam. Said first spacer member has a plurality of blocking portions which are formed on a rear side of said tabs to resist the tabs frontward so that the contacts can not move rearwards but be retained in the insulating housing stably even during the mating process with a mating connector.