Many troubles caused by problems in operation manuals happen in various industrial areas. The problems relate with each step of the process to create operation manuals, persons to describe operation manuals, and operators(workers). This paper analyzes trouble cases reported in a data base for oil refinery plants by an analysis method that the authors proposed by considering a process model of creating and using operation manuals. This paper also compares the analysis results with those of the trouble cases happened in nuclear power plants. Then, common tendencies of both plants and characteristic tendencies for each plant are discussed.