A vehicle seat comprises: a base frame (side frames 4, pipe frame 5) which constitutes left and right lower portions of a seat back frame; a force-receiving member (bracket 7) disposed adjacent to a left or right outer side of the base frame, and configured to receive a load from outside in a lateral direction; and a load transmission part (lower portion 51 and lower frame) configured to transmit the load from the force-receiving member to a side laterally opposite to that on which the force-receiving member is provided. The force-receiving member has a shape with a closed cross section, and a portion of at least one of the front wall and the rear wall (front wall 81) separate from upper and lower ends thereof provides an uneven shape (recessed portions 81a).