NOVELTY - Formation of an indium oxide film involves elecro-deposition or electroless-deposition process by using aqueous solution containing nitrate ion and indium ion, and nitrate ion, indium ion and tartrate respectively.    USE - Production of semiconductor element and solar cell as an antistatic coating material which can be applied to a transparent glass member and as a cover for an indicative part of an electronic device.    ADVANTAGE - The large area indium oxide film obtained by the use of electro- and electroless-deposition process has a uniform thickness, excellent transparency and a sufficiently high conductivity and a uniform property on a large area substrate at a high speed (a high deposition rate) and at a low substrate temperature without necessity of using a large scale apparatus. The indium oxide film can be provided at a reasonable production cost. It is possible to efficiently form an effective blocking layer comprising the indium film. The indium oxide film is never problematic even in the case of producing an organic electrophotographic photosensitive member. The indium oxide film is neither deteriorated nor eluted in the successive coating step.    DETAILED DESCRIPTION - Formation of an indium oxide film involves either immersing an electrically conductive substrate (1) and a counter electrode in an aqueous solution (A1) containing at least nitrate ion and indium ion and flowing an electric current between (1) and the counter electrode to form the indium oxide film on (1); or immersing a substrate (2) in an aqueous solution (B1) containing at least nitrate ion, indium ion and tartrate and treating (2) by (B1) at 10 - 60 degreesC to deposit the indium oxide film on (2).    An INDEPENDENT CLAIM is also included for the following:    (I) a photovoltaic element comprising at least a first transparent and electrically conductive layer, a semiconductor layer and a second transparent and electrically conductive layer stacked in this order on (1) or (2),at least one of the first and second layers comprising the indium oxide film;    (II) (1) or (2) for a semiconductor element; and    (III) (A1) and (B1) for the formation of the indium oxide film.