Vehicle seat

The utility model provides a seat for a vehicle, which can improve the strength of a side frame while inhibiting the weight increase of the seat. Since one end side of the nut (N) abuts against the first frame (230) and the other end side of the nut (N) is welded to the second frame (231), deformation such as expansion of the opposite interval between the first frame (230) and the second frame (231) can be limited by the extending part (N3) of the nut (N) and the head part of the bolt (B), and deformation such as narrowing of the opposite interval can be limited by the shaft part (N1) of the nut (N). As a result, when the load (Fb) from the backrest frame acts on the side frame (23), the side frame (23) can be prevented from collapsing and deforming. That is to say, the side frame (23) canbe reinforced by using the bolts (B) and the nuts (N) for connecting the backrest frame (5) to the side frame (23), so that the strength of the side frame (23) can be improved while the weight increase of the seat is suppres