To keep good circulation of blood in lower limb parts even when sitting on a high chair such as sitting on a narrow and high seat in an airplane under putting on a seat belt to prevent blood from danger of forming clots in a blood vessel and its flowing out to reach the lung or the heart to cause lung embolus, or the like.

It is preferable to remove compression on thighs from the lower side by placing support under user's feet for good blood circulation in the lower limb parts even when a user sits on a high chair. A hard flat plate for putting feet thereon and a support therefor, which allow user's feet to be put on for rest, are equipped on an ordinary bag for cabin without bringing in excessive articles.