Air supply device

The invention discloses an air supply device. The air supply device comprises a body, a mounting column and an air supply piece, wherein the body is provided with a rotating center; the mounting column is arranged on the body; the air supply piece is pivotally arranged on the mounting column and has a retracting position and a stretching position, and the distance between the free end of the air supply piece at the retracting position and the rotating center is smaller than the distance between the free end of the air supply piece at the stretching position and the rotating center; the air supply piece rotates from the retracting position to the stretching position under the action of centrifugal force through the rotating action of the body; and the air supply piece rotates from the stretching position to the retracting position under the action of self-gravity. Therefore, through cooperation of the body, the mounting column and the air supply piece, when the air supply device is not in use, the air supply p