Kanazawa Medical University has a clinical medicine building and another basic medical science building. The RI center is also installed in each building for education and studies. In these, the disposal and drainage facility is established as an outbuilding to a clinical study building, and had access by a drainage pipe to the RI center. In this time, the new medical education building will be constructed, and second floor part will be connected to the clinical study building through the roofed passage onto the disposal and drainage facility. At first, we received hearing with Nuclear Regulation Authority and confirmed that it is not a problem that the roofed passage goes on this facility. Then, we managed construction workers as temporary entrance person at one time and educated them. In addition, we decided to take a monthly report of personal dose of radiation exposure and the entrance record to the controlled area and started construction.