Main goal of our study was to resolve the difficulties in Problem/Project Based Learning (PBL) in high school or university level. To obtain good achievement in PBL, it is quite important for facilitators to effectively guide students. However, it is often the case that inexperienced teachers do not know the way of facilitation. To overcome this problem, we developed "PBL workflow model" so that teachers can make precise facilitation in accordance with each learning theme and learners' situations. To design the model, we initially categorized multiple works that build PBL on the basis of our previous practices of PBL and clarified the main issues in it. We then identified the relationships between the factors involved with PBL through careful investigations. Finally, we designed the model that illustrates the association of work groups, issue groups, and facilitation groups. Consequently, our methods enable teachers to conduct facilitation in accordance with more detailed situations in PBL than those of by existing methods. Moreover, our methods enable both of two conflicting policy (i.e., compliance with PBL standard while ensuring freedom of learning activities).