A charging plug includes a housing, two charging pins, and an elastic piece. The housing includes a main body portion having an arrangement surface and a protruding portion. The protruding portion is connected to the main body portion and located on the arrangement surface. The protrusion portion has an upper surface, a first side surface and a second side surface opposite each other and connecting to the upper surface. The charging pins are disposed in the housing and extend out of the protrusion portion. The elastic piece is disposed on the protruding portion of the housing and located between the charging pins. The elastic piece covers the first side surface, the upper surface and the second side surface and has at least one positioning portion, and the positioning portion is adapted to be engaged with at least one slot of a casing.