To provide a chair which prevents fingers from being pinched in a gap between a seat plate and a frame and also attains comfort by keeping an appropriate elastic deformation in the seat plate.

The seat plate 3 is supported on a seat reception frame and a gap 51 is formed between the upper surface of the seat reception frame and the lower surface of the seat plate 3. Elastic ribs 351 are integrally arranged to project from the lower surface of the seat plate 3 in an area with the gap 51 formed therein. Then, the distal ends of the elastic ribs 351 are brought into elastic contact with the outer surface of the seat reception frame in an inclination state.