Abstract: By using a plurality of images obtained by combining image of damage included in a road surface still image based on perspective and definitions of the damage as damage learning data, an object detection model is built. A plurality of data wherein the number of rectangles in an analysis result image displaying the rectangles surrounding the damage output as an analysis result of the object detection model and a pavement condition rating result obtained by visual inspection of the analysis result image of the object detection model are combined is used as condition rate learning data to build a rating estimation model, and pavement condition is rated using the rating estimation model.