Seat armrest, seat and vehicle

The embodiment of the utility model provides a seat armrest, a seat and a vehicle, relates to the field of vehicles, and is used for providing a small table board function. The seat armrest comprises an armrest base body, a first table plate and a first rotating mechanism. The armrest base body is provided with a base body table top. The first table plate is connected with the armrest base body through a first rotating mechanism; when the first rotating mechanism is unfolded, the first surface of the first table board is coplanar with the tabletop of the base body. According to the seat armrest provided by the embodiment of the invention, the function of a small table board can be provided, a larger and smoother supporting surface can be formed, and the flexibility, the stability and the practicability are relatively high.