The present invention relates to a method of manufacturing a molded article in the form of an optical element such as a glass lens by heat-softening a glass material such as optical glass and press molding it with high precision in a pressing mold as well as an objective lens for optical picking up. The method of manufacturing comprises press-molding a molding material to make a molded article, measuring an optical property of the molded article, correcting pressing rate of at least one of the pressing molds based on the optical property thus measured, and further press-molding to make a molded article with the corrected pressing rate. A pressing device comprising a pair of pressing molds having molding surfaces processed to prescribed shape, and a means of driving one of the pair of pressing molds at a prescribed rate to press mold a molding material supplied between the pressing molds is disclosed. The device further comprises a means for detecting an optical property, a shape or a number of the molded articles and a means for controlling driving of said means of driving by correcting pressing rate of the molds based on the detected property, shape or number.