Chair

A chair comprising:

• a seat having a lower surface in a vertical direction;
• a backrest tiltable with respect to the seat from an initial position;
• an elastic member having a first end portion connected to the backrest and a second end portion positioned forward of the first end portion in a first direction intersecting the vertical direction and connected to the lower surface of the seat;
• and
• a support structure supporting the lower surface of the seat and the backrest, wherein the support structure includes:
• a seat support shaft portion supporting the seat such that the seat is movable in the first direction;
• a back support shaft portion extending in a second direction intersecting the vertical direction and the first direction and supporting the backrest to be rotatable;
• and
• a position conversion mechanism rotatably supported with respect to the seat support shaft portion and the back support shaft portion and configured to convert a displacement of a position of the backrest caused by rotation of the backrest into a displacement of a position of the seat,
• the elastic member is configured to elastically deform in the vertical direction and the first direction due to the rotation of the backrest, and
• the elastic member is configured to apply a restoring force caused by the elastic deformation to the seat and the backrest to return the seat and the backrest to the initial position.