To sharply reduce the heat transfer from a roof by covering the sunny face of a structure with a shielding material having a low heat transfer rate, and using aluminum for the shielding material.

The sunny face of a structure 10 is covered with a shielding material 11 having a low heat transfer rate, and aluminum reflecting most of the incident light and sharply reducing the intruding heat transfer quantity is used for the shielding material 11. When aluminum is used for the shielding material 11, most of the sunlight is reflected and shielded at the shielding factor of about 0.15. This aluminum 30 is formed into a woven shape or a film shape, or aluminum is deposited on a specific base material. When the shielding material 11 is to be installed on the structure 10, a roll-like aluminum material is deployed on a roof while being rotated by a handle. The capacity of a cooling air conditioner can be decreased, and the heat permeation to the structure 10 can be suppressed.