A fan device for a computer host includes a rectangular container having an emplacement sink, a plurality of fans each of whose front and rear surfaces are provided with a plurality of latch holes, a plurality of positioning outer jackets made by a flexible material, and a plurality of positioning inner jackets made by a hard material and inserted into positioning holes of the positioning outer jackets, wherein an exterior edge of positioning outer jacket can be latched and positioned on an inner sink wall of the emplacement sink, so as to latch and fix the fans onto a casing of computer host without using screws, and to achieve the effects of absorbing vibration and reducing a noise at the same time.