A swivel device includes a base, a first gear fixed to the base, a tray configured to relatively rotate with respect to the base, a second gear fixed to the tray and engaged with the first gear so as to rotate together with the tray wherein the second gear has a smaller diameter than the first gear, a stopper wheel coaxially fixed to the second gear, and a stopper configured to stop rotation of the stopper wheel to fix a position of the tray.
