The purpose of this paper is to discuss more effective method of mathematical problem posing by using computer. The practice of problem posing is for some university students who want to become a teacher in the future. A feature of the method is to provide situations in which students make conjectures on results and get the numerical calculation by using computer. And another feature is to give students enough time to create problems. Actually, in the practice, some students had difficulty in making problems by using computer, but many students showed much originality in their problems, which might not be made without using computer. We observed the active learning activities which might not be observed in the usual classes. It is asserted that the opportunity of problem posing by using computer is very important.
