Electrical connector

An electrical connector to be connected to a mating connector, comprising:

• a housing having a groove;
• a terminal;
• a shield member having a slit;
• and
• a locking piece arranged in parallel to the terminal for engaging the mating connector and accommodated in the groove and the slit,
• wherein said locking piece includes a base portion;
• an arm portion movable by a specific amount;
• a fixing portion fixed to the housing;
• and a regulating portion fixed to the housing, said arm portion extending from the base portion toward the mating connector via a bent portion and having a locking portion for engaging an engaged portion of the mating connector at a distal thereof, said fixing portion extending from the base portion toward the mating connector, said regulating portion being situated on an opposite side of the fixing portion with respect to the base portion and extending from the base portion in a moving direction of the arm portion, said locking piece being accommodated in the groove and the slit so that the arm portion bends into the groove through the slit when the electrical connector is connected to the mating connector,
• wherein said regulating portion includes a narrow width portion situated on a side of the base portion and a wide width portion situated on a side of a free edge thereof.