An electronic device includes a magnetic switch, a magnetic element for actuating the magnetic switch to send a control signal to an electronic element module, and a retaining mechanism for retaining the magnetic element at a housing. The retaining mechanism includes a retaining casing, a connecting member, and a blocking member. The retaining casing is disposed on and cooperates with the housing to define a receiving space to receive the magnetic element, and has an opening in spatial communication with the receiving space. The blocking member is connected to the housing by the connecting member and is adjacent to the opening to prevent removal of the magnetic element from the receiving space through the opening.