Sequential contrd　is　one　of　contrQl　techniques　used　for　automated　process operation．By　the　sequentlal　control，the process　is　operated　automatically　in　according with　the　procedure　which　has　be　ordered　for　the　process．And　it　is　widely used　for　automatic　operatioll　control　in　chemical　plalnts　and　nuclear　energy　plants． This　paper　presents　an　algorithm　for　app／icatioll　of　knowledge　engilleering　to　automated　fault　tree　synthesis　for sequentlakontrol　circuits．The　lnformation　about　components　connection　fn　sequential　control　circuits　is inputted　into computer　as a　line　kllowledge　base、Component　malfunctiou　information　is　stored　in　the　form　of　mini　fault　tree， Signal　path　in　the　circuit　are　found　by　searching　through　the　line　knowledge－base　and　trallsformed　into　the　signal　flow knowledge－base，which describe　inforlnation　of　signal　path．Accordillg　to　signal　path　information in　the　signal　flow knowledge・base，mini　fault　trees　of　compollents　are　combined　followiIlg　and　fault　tree　is　constructed． Automated　fault　tree　synthesis　is　demonstrated　for　simple　motor　control　circuit　to　show　the　basic　algorithm.