NOVELTY - A thin film photoelectric conversion apparatus has a transparent electrode layer (2), thin film photoelectric conversion unit (31,33), and back surface electrode (5). A transparent conductive oxide layer (4) containing zinc oxide and electroconductive additive is formed between conversion unit and electrode. The additive consists of silicon atoms (85 atomic% or more). The amount of silicon atom with respect to zinc atom in oxide layer is 2-8 atomic%. The oxide layer is formed since silicon is tetravalent when seen in X-ray photoelectron spectroscopy of conductive oxide.    USE - Thin film photoelectric conversion apparatus e.g. thin film solar cell.    ADVANTAGE - The thin film photoelectric conversion apparatus has high wet heat durability and improved power generation characteristics.    DETAILED DESCRIPTION - A thin film photoelectric conversion apparatus has a transparent electrode layer consisting of a transparent conductive oxide from light incidence side, at least one thin film photoelectric conversion unit, and a back surface electrode arranged in order. A transparent conductive oxide layer containing zinc oxide as main component, and electroconductive additive is formed between conversion unit and back surface electrode. The additive consists of silicon atoms (85 atomic% or more). The amount of silicon atom with respect to zinc atom in oxide layer is 2-8 atomic%. The transparent conductive oxide layer is formed since silicon is tetravalent when seen in Si2P1/2 peak in X-ray photoelectron spectroscopy of conductive oxide. An INDEPENDENT CLAIM is included for manufacture of thin film photoelectric conversion apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of thin film photoelectric conversion apparatus.    Substrate (1)    Transparent electrode layer (2)    Photoelectric conversion layer (3)    Transparent conductive oxide layer (4)    Back surface electrode (5)    Thin film photoelectric conversion units (31,33)    Electroconductive oxygenated silicon layer (32)