To complete a stop procedure or emergency countermeasure procedure in dealing with accident by previously simulating an insertion procedure by the operation guide system by a computer and sequentially illuminating switches on the panel according to the procedure.

Operation data on the actuation and stop of a nuclear reactor are inputted from an input device 5 to an arithmetic processing 1. Illuminating switches 7 are installed on the input device 5 and the insertion procedure is previously simulated by the computer to turn on the illuminating switches 7 according to the operation data inputted to the arithmetic processing 1 by following the insertion procedure. Namely, the operation data are processed by the arithmetic processing 1, the result of the arithmetic operation is supplied to a storage device 2, and illumination data as part of the operation data are transmitted to the illuminating switches 7 from an operation procedure process part 1b according to operation conditions and environment.