The slip & fall accidents occur very often and seriously in daily life. The serious slip & fall accidents occurs more and more frequently due to aging society. The mortality due to slip & fall accidents increases year by year. The number of injured persons due to slip & fall accidents are several tens of times of mortality. Following the rise of consumer awareness, prevailing of Consumer Protection Act, simplification of litigation, the slip & fall related actions are increasing. Since the facility administrator and owners are responsible for the facilities management, the claims for medical expenses and losses are increasing, too. Therefore, the anti-slip ground of building facilities is getting important.