First, the authors point out the necessity to assess all stages of tasks (planning, meeting with contractors, performing phase of task, etc.) in risk assessment (RA) for operation and maintenance tasks in electric power company, because most maintenance tasks are performed by contract system and risks are distributed over electric company, contractors and subcontractors. Secondly, risks estimated from past accidents and near-miss events must be included. If these 2 requirements are fulfilled, data of RA can be more useful. Then 4 forms of present data of RA were developed. Additionally, a data base system of RAs for 4 tasks was developed. This system prints out these 4 forms for each task and is useful for every-day safety activities.