To solve the point at issue that the conventional photocatalyst body is constituted so as to enhance the decomposition and removal capacity of a harmful substance of the photocatalyst body as a whole by increasing the total surface area of a photocatalyst film to increase the contact chance of the harmful substance with the photocatalyst body but the adsorbing capacity thereof is lowered because almost all of the pores of the photocatalyst are closed with the photocatalyst film and the decomposition and removal capacity of the photocatalyst body is not improved to an expected degree.

This manufacturing method of the photocatalyst body includes a process (1) for preparing a raw material solution for forming a photocatalyst layer, a process (2) for heating adsorbent having empty pores communicating with the open air, a process (3) for spraying the stock solution to apply the same to the surface of the adsorbent and a process (4) for baking the adsorbent coated with the stock solution to form the photocatalyst layer on the surface of the adsorbent.