A method of manufacturing resin articles with naturally formed patterns is provided. The method uses organic matter, such as portions of a fern like the "Sphaeropteris lepifera", and a resin, to be molded together and then machined into a desired shape. The inner surfaces of the upper mold section and the lower mold section are covered by aluminum foil sheets and enclose a portion of a fern, such as the "Sphaeropteris lepifera" therein. A resin is injected into the mold through an opening in one foil sheet and the mold is heated to an appropriate temperature. Subsequently, the mold is cooled by room temperature air and dried by a drying machine. The resin is removed from the mold and machined into a particular shape in accordance with a predetermined design. The shaped molded resin is smoothed by grinding or filling in uneven portions with resin. After smoothing, the molded resin is polished to provide a naturally-formed pattern on the surface thereof.