One of the serious problems of distance learning systems is how to teach many students on an individual basis. The authors design an educational method, dynamic group guidance using quiz functions for network based lecturing, and present an implementation method. Using the dynamic group guidance function, the system groups students automatically according to the results of quizzes and a teacher can guide each group individually. Supported by the system, therefore, a teacher can guide every student in a lecture efficiently according to his/her own level of understanding. We have realized the system using two technologies: user profiling and software agents.