A new application of the factorization method is reported for 3-D shape reconstruction from endoscope image sequences. The feasibility of the method is verified with some theoretical considerations and results of extensive experiments. This method was developed by Tomasi and Kanade, and improved by Poelman and Kanade, with the aim of achieving accurate shape reconstruction by using a large number of points and images, and robustly applying well-understood matrix computations. However, the latter stage of the method, called normalization, is not as easily understandable as the use of singular value decomposition in the first stage. In fact, as shown in this report, many choices are possible for this normalization and a variety of results have been obtained depending on the choice. This method is easy to understand, easy to implement, and provides sufficient accuracy when the approximation used for the optical system is reasonable. However, the details of the theoretical basis require further study.