SEAT DEVICE FOR VEHICLE

A seat device for a vehicle is provided in which a dynamic damper (D) is formed of a weight (15) and an elastic member (16) supporting the weight (15) so as to be capable of vibrating, and the elastic member (16) is retained on a frame (6, 10, 12) or a cushion member (13) of a seat (S) installed in the vehicle, wherein the weight (15) is formed into a polyhedron whereas the elastic member (16) is formed into a sheet shape, and the weight (15) is covered and supported by the sheet-shaped elastic member (16). This enables the weight to be supported simply by the elastic member, and the dynamic damper to be provided at low cost.