1. A geometric modeling system comprising: a processing unit configured for creating a geometric model, and creating a meshed analytical model to analyze the geometric model; a storage unit for storing the geometric model and the analytical model; said processing unit being further configured 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; creating and storing correlation data showing relations between geometric elements of the object geometric model and nodes of the object analytical model; modifying the object analytical model and creating a modified analytical model; 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 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.