A waterproof mechanism includes a housing having a base wall, at least one door plate, a first waterproof seal, and at least one return spring. The base wall is formed with an opening. The door plate is connected movably to the base wall for closing the opening in the base wall. The door plate is pushable to perform a motion relative to the base wall to thereby open the opening. The first waterproof seal is disposed between the base wall and the door plate and around the opening so as to establish a water-tight seal between the base wall and the door plate. The return spring is disposed between the base wall and the door plate for biasing the door plate to close the opening.