The 2005 West Off Fukuoka Earthquake caused very seirous slope disasters in the Shiga Island. There are three areas where slope collapse occurred. The slope disasters, investigation and analysis, and the countermeasures in the restoration for the collapsed slopes are introduced in this paper. For the small-scale collapses, occurred in Kou area and Kurose area, the urgent restoration work was performed immediately after disaster based on the joint survey results by the two investigation commissions, organized by Japan Society of Civil Engineers and Japanese Geotechnical Society. However, for the large-scale slope collapse generated in the Shiga Sea Shrine area, since the large cave-in geographical feature with large deformation was formed on the top side of the collapses, it is anxious that a large-scale collapse will occur induced by future earthquakes or heavy rains. Therefore, more detailed investigation and analysis were conducted, and the countermeasures in the restoration work was planned and implemented based on the risk analysis results. Moreover, it was shown clearly that we need to learn more from the disasters and reexamine the way of the slope disaster prevention in this paper.