An electronic device including a circuit board, a first housing, a second housing, and a third housing is provided. The circuit board has at least one connector on at least a first side of the circuit board. The first housing and the second housing are connected and form a containing space and an opening. The circuit board is disposed in the containing space and the first side thereof is at the opening. In addition, the third housing covers the opening and has at least one connector hole. Furthermore, the connector is at the connector hole. The housings of the electronic device are easy to be assembled and maintained and the cost of replacement is low.