In recent years, it has been widely acknowledged that classes designed by utilizing PBL (Project-Based Learning) are effective in enhancing the problem-solving ability of university students. In PBL-based classes, students try to apply their knowledge to solve the problems by themselves; therefore, such classes are effective in improving problem-solving and communication abilities of students. However, it is difficult for a teacher to appropriately assess individual contributions in a group work such as PBL. Since 2002, we have been planning and conducting group-work-based software development experiments as an approach to PBL. This paper describes the manner in which the class was designed and conducted in order to evaluate the contribution of each individual student based on the degree of achievement of a goal in a group work. We propose an evaluation method based on an evaluation model of PBL and discuss the trial results.