The mechanical clock was designed and produced by students as a trial theme of PBL class. The limit of making time is three weeks and main material is limited to paper. Only a basic mechanism drawing is given. As the principle of mechanical clock is not complex and does not need the special knowledge of mechanical engineering, even lower grade student seems to understand enough. This subject can train the skill of knowledge composition, creativity and the problem-solving ability. After execution,the validity and performance as the theme of PBL class was evaluated. As a result, the following findings were obtained. The paper made mechanical clock could be produced in three weeks. And, by additional improvements of the product, the enough strength and stable movement were achieved. Students can learn that many kinds of knowledge through actual experiences of design and making were required in manufacturing the real products. The proposed PBL style class is suitable as an introduction and training subject for lower grade student in department of engineering.