1. A geometric modeling system comprising: means for creating a geometric model; means for storing the geometric model; means for creating a meshed analytical model to analyze the geometric model; means for storing the analytical model; means for specifying and reading a geometric model to be modified (hereinafter called “object geometric model”) and an analytical model to be modified (hereinafter called “object analytical model”) from the stored data; means for creating and storing correlation data showing relations between geometric elements of the object geometric model and nodes of the object analytical model; means for modifying the object analytical model and creating a modified analytical model; means for extracting nodes of the modified object analytical model from the correlation data, the nodes being related to geometric elements of the object geometric model, determining whether coordinates of the extracted nodes in the modified object analytical model are included in coordinates of the geometric elements of the object geometric model, and extracting geometric elements which do not include the extracted nodes; and means for performing a geometric fitting process so as to fit the extracted geometric elements to the nodes, and creating a modified object geometric model from the modified object analytical model.