The continuous fatal accidents like explosion or fire cause huge losses of both life and property in laboratories even though safety management system has been built and periodical checkups and safety diagnosis have been implementing in universities and enterprise-affiliated research institutes since Act on the Establishment of Safe Laboratory Environment was enacted in 2005 to prevent accidents in research laboratories. Cause analysis and safety management measures to prevent recurrence of accidents are urgently needed because accidents in research laboratories occur repeatedly with similar contents. This study will show results of analysis on incidents and accidents occurred in laboratories in universities and enterprise-affiliated research institutes using Root Cause Analysis Method and propose classified map of cause investigation and improvements so as to improve safety management in research laboratories.