A power outlet includes a casing, a middle-layer support and at least one safety shield device. The middle-layer support includes at least one conductive plug bush and provides guiding jacks corresponding to the position of the conductive plug bush. The safety shield device has a left shield, a right shield and a spring. Each left and right shield extends a shield foot from the underside, respectively. The middle-layer support further includes sliding platforms for movement of the left shield and the right shield. The sliding platform has location holes for insertion of the shield feet. When the left shield and right shield lock, two shield feet respectively match against an opposite inner edge of two location holes on the sliding platform. When the left shield and right shield open, the guiding jack on the middle-layer support exposes.