Making a report with an authenticated image includes certifying an imaging time of an image captured by a portable terminal with a camera with an objective time to authenticate image information. A report making program for making a work report is downloaded in the portable terminal by a Web browser from a web server. Report data such as an image and information inputted according to the report making program is sent from the portable terminal to the web server. The web server transfers the report data to a document management program. The document management program automatically sorts the report data according to an information category of the report data and stores the report data. The imaging time of the image information included in the report data or the image information contained in the report made based on the report data is authenticated with a reference time of the web server.