A horse body information provision system comprising: a moving image data storage device for storing moving image data of a horse entered in a race in association with horse information identifying the horse entered in the race; a still image data extraction device for extracting, from first moving image data captured at a first point in time, first still image data representing a horse in a posture close to a horse body posture shown in a sample image from the moving image data stored in the moving image data storage device, and for extracting, from second moving image data captured at a second point in time different from the first point in time, second still image data representing the horse in a posture close to the horse body posture shown the sample image; a still image data storage device for storing the first and second extracted still image data in association with the horse information; a generation device for generating Web page data to display the first still image data and the second still image data associated with the horse information, in response to a user selecting a link in a Web page to acquire and display the still image data on a terminal device (3-k); and a distribution device for distributing the generated Web page data to the terminal device (3-k), wherein: the still image data extraction device converts the sample image into a mosaic image, the mosaic image being an image in which a resolution of the sample image is reduced, extracts temporary still image data from each of frames included in the moving image data by scanning each frame using the mosaic image, the temporary still image data representing an area closest to the sample image for each frame, ranks the temporary still image data extracted per frame according to a similarity with the sample image, and extracts the temporary still image data closest to the sample image as the still image data from the temporary still image data. a moving image data storage device for storing moving image data of a horse entered in a race in association with horse information identifying the horse entered in the race; a still image data extraction device for extracting, from first moving image data captured at a first point in time, first still image data representing a horse in a posture close to a horse body posture shown in a sample image from the moving image data stored in the moving image data storage device, and for extracting, from second moving image data captured at a second point in time different from the first point in time, second still image data representing the horse in a posture close to the horse body posture shown the sample image; a still image data storage device for storing the first and second extracted still image data in association with the horse information; a generation device for generating Web page data to display the first still image data and the second still image data associated with the horse information, in response to a user selecting a link in a Web page to acquire and display the still image data on a terminal device (3-k); and a distribution device for distributing the generated Web page data to the terminal device (3-k), wherein: the still image data extraction device converts the sample image into a mosaic image, the mosaic image being an image in which a resolution of the sample image is reduced, extracts temporary still image data from each of frames included in the moving image data by scanning each frame using the mosaic image, the temporary still image data representing an area closest to the sample image for each frame, ranks the temporary still image data extracted per frame according to a similarity with the sample image, and extracts the temporary still image data closest to the sample image as the still image data from the temporary still image data. the still image data extraction device converts the sample image into a mosaic image, the mosaic image being an image in which a resolution of the sample image is reduced, extracts temporary still image data from each of frames included in the moving image data by scanning each frame using the mosaic image, the temporary still image data representing an area closest to the sample image for each frame, ranks the temporary still image data extracted per frame according to a similarity with the sample image, and extracts the temporary still image data closest to the sample image as the still image data from the temporary still image data.