A seat apparatus for a vehicle, includes a seat-side fixing member, a slide rail, a load detecting device disposed between the seat-side fixing member and the slide rail and arranged at an end portion of the slide rail on a rear side of the vehicle, and a bracket arranged at an end portion of the slide rail on a front side of the vehicle, the bracket supporting the seat-side fixing member. The bracket includes a lower attachment portion attached to the slide rail, a supporting portion extending from the lower attachment portion toward an upper side of the vehicle, and an upper attachment portion connected to the supporting portion so as to extend from the supporting portion toward the rear side of the vehicle, thereby being cantilever-supported by the supporting portion, and attached to the seat-side fixing member at a free-end side of the upper attachment portion.