Abstract: A swivel chair having a body-fit structure is provided with a movable seat, a chair frame, an adjustable stud, a seat cushion split into two arched halves, springs, two sliding blocks, two fixing plates, and an extensible shade. The movable seat having octopus-like legs extending radiatedly provides the supporting footing at the bottom. The two arched halves of the seat cushion are supported by the fixing plates and the sliding blocks. The fixing plates are fixedly secured to the bottom of the two arched halves of the seat cushion, and engaged with the sliding blocks by inserting pins at one side and springs at the other side.