Various types of fatal accidents are increasing in Korean construction work site. Simply repeated and conventional accidents as well as new types of potential hazards which are caused by large-scaled work, complexity and negligence of temporary structures in construction are increasing, so that analysis of fundamental causes are necessary to control the construction accidents. In this study 739 fatal accidents are informally classified by the types of work and work process. The classified items which are based on ANSI Z 16.2, are modified adapted to the construction fields and are given code numbers and are analyzed by the data-base program. The exact causes of various types of accidents are analyzed by the accident types, agencies and hazardous conditions and through the Cross-tabulation method in order to find out the cause between relevant accidents.