NOVELTY - The element (40) has a substrate (10) comprising an aluminum base material (14) laminated on a metallic substrate (12). An insulating layer (16) is formed as an anodized film of aluminum in a surface of the aluminum base material and a stress relaxation layer (50) is formed on the insulation layer. A back surface electrode (32) is formed on the stress relaxation layer. A photoelectric converting layer (34) is formed on the electrode. A transparent electrode (38) is formed on the photoelectric converting layer.    USE - Photoelectric conversion element for thin film solar cell (claimed) used in electric power generation.    ADVANTAGE - The stress relaxation layer is formed on the insulation layer, thus suppressing generation of crack and peeling of the insulation layer. The stress produced by difference in the thermal expansion coefficient of each layer in the photoelectric conversion element is relieved by the stress relaxation layer, thus suppressing peeling of the layers of the photoelectric conversion element even if temperature-falls to room temperature while forming the back surface electrode, the photoelectric converting layer and the transparent electrode. The photoelectric conversion element is formed by passing through film-forming process at a temperature of 500 degree Celsius or more, thus maintaining high insulating property and high intensity of the photoelectric conversion element, and hence improving photoelectric transfer characteristic of the photoelectric conversion element. The stress relaxation layer functions as an electric-insulation layer, thus improving insulation property of the photoelectric conversion element, and hence improving withstand voltage property. The stress relaxation layer is formed of an alkali metal, thus improving photoelectric conversion efficiency while improving high temperature tolerance.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a photoelectric conversion element manufacturing method.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a thin film solar cell comprising a photoelectric conversion element.    Substrate (10)    Metallic substrate (12)    Aluminum base material (14)    Insulating layer (16)    Back surface electrode (32)    Photoelectric converting layer (34)    Transparent electrode (38)    Photoelectric conversion element (40)    Stress relaxation layer (50)