Abstract: A vehicle seat includes a seat back and a cushion seat. The cushion seat includes a seat frame, a cushion pad portion above the seat frame, a first submarining suppression portion below the cushion pad portion, and a second submarining suppression portion below the cushion pad portion, the second submarining suppression portion arranged on a side of the first submarining suppression portion closer to the seat back.

Abstract: A connection bar mounting structure includes: link members, each including a first hole part in a middle part; vehicle members, each configured to rotatably support each link member at a first fixation part of each link member; side frames, each configured to rotatably support each link member at a second fixation part of each link member opposite to the first fixation part across the first hole part; and a connection bar, each end thereof fixed to the first hole part of each link member. Each link member has a first bending rigidity reduced section between the middle part and the first fixation part and a second bending rigidity reduced section between the middle part and the second fixation part, the first and second bending rigidity reduced sections having bending rigidity smaller than those of the middle part, the first fixation part, and the second fixation part.