[en] The 'Mizunami Underground Research Laboratory', one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the crystalline bedrock conditions, specifically the rock mass geology and hydrogeology. Therefore, borehole investigations were conducted before excavations. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting with cement was conducted around Ventilation Shaft and Access/Research Gallery before excavations. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting. A CD-ROM is attached as an appendix. (J.P.N.)