To obtain a light and inexpensive tropical cap having a simple structure.

The surface of the outside of a helmet 1 is coated with a heat insulating coating material 2, for example, in ≥400 μm thickness of coating film. The heat insulating coating material 2 is, for example, a mixture obtained by impregnating fine particles of various silicas and ceramics and an acrylic binder with a rigid latex base. Most (about 75%) of radiation heat energy of direct sunshine irradiated on the surface of the outside of the helmet 1 is reflected on the heat insulating coating material 2. Most (about 85%) of radiation heat energy not reflected is absorbed in the heat insulating coating material 2 and released again in all directions of the surface of the outside. Consequently radiation heat energy released in the interior of the helmet 1 is slight (about 4%).