A fuel cap has a cap main body, a cover with a handle, and a torque mechanism. The torque mechanism includes a torque transmission unit and click units. When the handle is rotated in a closing direction, torque is transmitted to a cantilever spring of the torque mechanism. The cantilever spring is deformed by rotation of the cover in the closing direction. After the spring is deformed by a predetermined amount, in response to rotation of the cover with respect to the cap main body by at least a preset angle, the click units make a click sound. When the user releases the handle, the spring force of the cantilever spring restores the click units to their initial positions. The cap device has a torque mechanism that has a simple structure and consists of a small number of parts.