A method for producing a metal oxide and plant for producing a metal oxide

An object of this invention is to provide a method for forming a metal oxide in which the temperature of a heat treatment of a substrate can be lowered, and can give a metal oxide film having a low resistance value also, without limiting the kind of the forming metal oxide. The method for forming a metal oxide film according to this invention comprises (A) converting a solution (4, 8) comprising a metal, in fog, (B) heating a substrate (2) and (C) supplying the converted into mist solution and ozone to a first main surface of the substrate under heating.