To provide an indoor coating solvent and a method of coating, safe to the human body, with immediate effectiveness and sustainability for the decomposition and removal of volatile contamination chemical substance generated indoors, deodorization in the interior, sterilization and mildewproofing, regardless of conditions such as the lightness in the interior.

The cleaning effect, immediate effectiveness, sustainability and compatibility of the indoor coating solvent are improved by mixing phytoncide, titanium oxide, and titanium phosphate compounds; and a coating film can be formed by simple aerosol spray, etc. of various kinds.