A foldable mobile electronic device includes a body, a top cover and a hinge. The body includes a first sliding mechanism. The top cover includes a second sliding mechanism moving between a first position and a second position relative to the body. The hinge includes a first protrusion and a second protrusion. The first protrusion corresponds to the first sliding mechanism and the second protrusion corresponds to the second sliding mechanism. When the top cover is in the first position, the hinge extends from the body and the top cover to be exposed, and when the top cover is in the second position, the hinge is accommodated in the foldable mobile electronic device.