To provide a seat in which a surface of a back rest and a surface of a bottom face of the seat are approximately vertical, storage arrangement that length of the whole length and height in a cabin are restricted is provided and further, handling in the case of changing a position of the seat is easy.

The structure of the automobile seat is provided with a frame 11 connected to a floor 5; a back rest 2 having a back rest surface 20 and connected to the frame 11; and a seat bottom face 4 assembled so as to be rotated on the frame 11 making a seat bottom face rotation axis B as an axis and having a seat bottom face surface 40. The structure can adopt sittable arrangement that the back rest 2 is slightly rearwardly inclined and the seat bottom face surface 40 is approximately horizontal and storage arrangement that the back rest surface 20 and the seat bottom face surface 40 become approximately vertical. The back rest 2 is mounted so as to be rotated on the frame 11 making a back rest rotation axis A as an axis and connection means 21, 23 for controlling rotation of the seat bottom face 4 that forward rotation of the back rest 2 is a direction opposite to the rotation direction of the back rest are provided between the back rest 2 and the seat bottom face 4.