It is an object of this invention to provide an optical element molding method capable of correcting local processing errors in an optical element without increasing the size of an apparatus or raising the manufacturing cost. To achieve this object, an optical element molding method includes the first step of setting molding conditions before molding of said optical element, such that a constant shape error is stably formed on an optical function surface of the optical element, the second step of dividing the optical function surface of the optical element to be molded under the molding conditions into a plurality of regions, and approximating the shape error by using a function so that the divided regions are continuous in the boundaries between the regions, the third step of processing the shape of the cavity surface of the optical-insert member into a shape by which the constant shape error is canceled, on the basis of the function obtained in the second step, and the fourth step of molding the optical element by using the optical insert member processed in the third step.