NOVELTY - A substrate (10) laminated with lower electrode (20) and photoelectric converting layer (30), is immersed in reaction liquid having pH of 9-13, at 25-45 degrees C, and maintained, such that zinc ion is diffused into photoelectric converting layer. Reaction liquid contains alkali chemical chosen from zinc source, and ammonia and/or ammonium salt. The resultant substrate is further immersed in reaction liquid at 55-90 degrees C, and zinc oxide layer as high-resistance oxide layer (50) is deposited on photoelectric converting layer to obtain photoelectric conversion element (1).    USE - Manufacture of photoelectric conversion element used for solar cell and charged-coupled device.    ADVANTAGE - The method efficiently and economically provides photoelectric conversion element, by simple method. Zinc oxide film is directly formed on the photoelectric converting layer surface of photoelectric conversion element, without forming n-type buffer layer. The damage of photoelectric converting layer surface is suppressed during manufacture of photoelectric conversion element.    DETAILED DESCRIPTION - A substrate laminated with a lower electrode and a photoelectric converting layer, is immersed in a reaction liquid having pH of 9-13, at 25-45 degrees C, and maintained for specified time, such that zinc ion is diffused into the photoelectric converting layer. The reaction liquid contains alkali chemical having concentration of 2M or less, chosen from zinc source having concentration of 0.1 M or more, and ammonia and/or ammonium salt. The resultant substrate is further immersed in the reaction liquid at 55-90 degrees C, and zinc oxide layer as high-resistance oxide layer is deposited on the photoelectric converting layer to obtain photoelectric conversion element having laminated structure of lower electrode, photoelectric converting layer containing compound semiconductor layer, high-resistance oxide layer and translucent conductive layer (60), on substrate.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of photoelectric conversion element.    Photoelectric conversion element (1)    Substrate (10)    Lower electrode (20)    Photoelectric converting layer (30)    High-resistance oxide layer (50)    Translucent conductive layer (60)    Upper electrode (70)