Provided is a vehicle seat in which the transmission direction of deformation of a seat when an impact load is applied thereto is diffused so that impact absorbability is improved. This vehicle seat includes a seat back having a seat back frame that serves as a framework. The seat back frame has side frames positioned on the left and right sides, and a lower frame connecting lower parts of the side frames. The lower frame has a weakened part that is deformed when an impact load is applied, and a deformation guiding part for guiding the deformation direction of the weakened part. The weakened part and the deformation guiding part are arranged in the centers of areas obtained by extending the center portion of the lower frame toward the right and left sides with the same vertical-direction width, are provided on the same horizontal plane.