A fan device for use in an electronic apparatus is proposed, the fan device being installed adjacent to a back-panel formed with an emitting diode component and composed of: a fan body, a fastening member and a light-guiding member, wherein the fan body is provided with a plurality of positioning holes for accommodating the light-guiding member, which is then fastened by the fastening member such that the end of the light-guiding member is close to the back panel to provide for a light source by means of the emitting diode of the back panel, allowing the light-guiding member to receive and guide the light to the front of the fan body, whereby the use can observe and judge if the fan device works normally or not from the varied brightness of light shown by the light-guiding member.