To obtain a sunshade that can be applied to a variety of children's seats or the like and folded compactly, is heat insulating and can be applied to uses such as protection of a child from the cold.

The sunshade 10 is mounted to a children's seat 30 and used to prevent the children's seat 30 from being heated by direct sunlight or the like. The sunshade 10 is formed as a flexible bag of a double layer structure consisting of an aluminum coated material as a surface fabric and a pile fabric as a lining. Therefore, by squeezing the opening 16 by a squeezing string 22, it can be mounted to a variety of sizes of children's seats, the surface fabric prevents direct heat transfer and the lining prevents indirect heat transfer when the surface fabric gets hot. It can be mounted to non-children's seat products and can be used for keeping a child warm, using the lining as a pile fabric.