To attain the advantageous winding behavior of a sunshade fabric at the ratio of optimum force at the time of delivery and drawing-in and in high stability to a wind.

The joint arm sunshade has at least two joint arms, each joint arm contains an internal joint arm section and an external joint arm section, these sections are combined mutually through a swivel joint, the gas spring is arranged between the internal joint arm section and the external joint arm section, and the gas spring works in the directions of positions extended to the joint arms. Elastic force in the delivery direction (a characteristic curve section) differs from that in the drawing-in direction (the characteristic curve section) in the gas spring 17, particularly the gas spring 17 has force, a path and a characteristic curve lower than those in the drawing-in direction.