Vehicle seat

A vehicle seat comprising:

• a seat frame that is provided as a strength member and extends in a specific direction, the seat frame including:
• a closed section frame having a closed sectional shape and extending in the specific direction,
• an opened section frame having an opened sectional shape and extending in the specific direction in parallel with the closed section frame,
• wherein the opened section frame is coupled with the closed section in a state to have a closure forming part and a gradually changing structure,
• wherein the closure forming part forms a closed sectional shape between the opened section frame and the closed section frame, and
• wherein the gradually changing structure changes the closed sectional shape formed between the opened section frame and the closed section frame at the closure forming part,
• wherein the open section frame has a first bottom plate,
• wherein the closed section frame has a second bottom plate, and
• wherein the first bottom plate and the second bottom plate are separated from each other by a separation distance in a height direction.