To provide an installation method of a waterproof and impervious sheet capable of reducing frictional resistance with substrate in the case of letting out the sheet on the spot even if it is a roll of a wider and longer waterproof and impervious sheet, lightening the burden imposed on pulling out work by a worker and more easily carrying out the pulling out work of the sheet even by a small number of workers.

In a state to separate the roll 3 winding the waterproof and impervious sheet 1 thereon from the substrate 5, the waterproof and impervious sheet 1 is pulled out of a core material 2 to expand and is installed in a state to surface the sheet 1 with wind pressure by sending a wind between the waterproof and impervious sheet 1 and the substrate 5.