Construction machinery has been utilized to carry out construction works effectively. Using construction machinery enables a builder to reduce the time and the cost needed for the construction, but the fatal accident caused by it has been increased. This study is intended to identify risk magnitude of accident by kind of construction machinery through interviews with experts. Construction machineries surveyed in this research are excavator, tower crane, lift, mobile crane and forklift, those are the machinery which accident occurs more often than the other machinery. To evaluate the risk of the accidents identified, risk category was determined according to the US DOD system safety program (MIL-STD-882B) considering the risk degree and intensity. As a result, accident occurred in the process of material transport & handling was found to be the most dangerous. On the other hand, the accidents caused by the defective machinery and the poor safety gear were considered to be less dangerous relatively. The risk category by type of construction machinery suggested in this study is expected to provide the basic data in developing the safety guidance for construction project.