A process for producing a thin film solar cell module comprising a plurality of thin film solar cells each comprising a substrate, and a transparent electrically conductive oxide film, an overcoat film, a photoelectric conversion layer and a rear electrode layer laminated in this order on the substrate, the layers on the substrate being divided by a plurality of dividing grooves (P1,P2) in a direction substantially vertical to the substrate, and the adjacent thin film solar cells being electrically connected in series, the process comprising: a step of forming the transparent electrically conductive oxide film on the substrate, a step of forming the overcoat layer, on the transparent electrically conductive oxide film and a step of patterning the transparent electrically conductive oxide film and the overcoat film by forming a first dividing groove in the transparent electrically conductive oxide film and the overcoat film, by a laser scribing method to divide the transparent electrically conductive oxide film and the overcoat layer; a step of forming the photoelectric conversion layer in the first dividing groove and on the overcoat film and a step of patterning the photoelectric conversion layer by forming a second dividing groove in the photoelectric conversion layer by a laser scribing method to divide the photoelectric conversion layer and a step of forming the rear electrode layer in the second dividing groove and on the photoelectric conversion layer and a step of patterning the rear electrode layer and the photoelectric conversion layer by forming a third dividing groove in the rear electrode layer and the photoelectric conversion layer by a laser scribing method to divide the rear electrode layer and the photoelectric conversion layer: wherein the step of patterning the photoelectric conversion layer is carried out so that the bottom of the second dividing groove is located in the transparent electrically conductive oxide film; and wherein the overcoat fim is a film containing titanium oxide as the main component and containing tin oxide. a step of forming the transparent electrically conductive oxide film on the substrate, a step of forming the overcoat layer, on the transparent electrically conductive oxide film and a step of patterning the transparent electrically conductive oxide film and the overcoat film by forming a first dividing groove in the transparent electrically conductive oxide film and the overcoat film, by a laser scribing method to divide the transparent electrically conductive oxide film and the overcoat layer; a step of forming the photoelectric conversion layer in the first dividing groove and on the overcoat film and a step of patterning the photoelectric conversion layer by forming a second dividing groove in the photoelectric conversion layer by a laser scribing method to divide the photoelectric conversion layer and a step of forming the rear electrode layer in the second dividing groove and on the photoelectric conversion layer and a step of patterning the rear electrode layer and the photoelectric conversion layer by forming a third dividing groove in the rear electrode layer and the photoelectric conversion layer by a laser scribing method to divide the rear electrode layer and the photoelectric conversion layer: wherein the step of patterning the photoelectric conversion layer is carried out so that the bottom of the second dividing groove is located in the transparent electrically conductive oxide film; and wherein the overcoat fim is a film containing titanium oxide as the main component and containing tin oxide. wherein the step of patterning the photoelectric conversion layer is carried out so that the bottom of the second dividing groove is located in the transparent electrically conductive oxide film; and wherein the overcoat fim is a film containing titanium oxide as the main component and containing tin oxide.