A plant control device of the present invention includes a register configured to register a simulated dangerous condition which is a simulated representation of an operation condition under which a plant is dangerous, a first acquirer configured to acquire an operation condition of the plant, a learner configured to learn the operation condition acquired and the simulated dangerous condition registered and produce an operation model of the plant, a determiner configured to determine an operation parameter of the plant on the basis of the operation condition acquired and the operation model produced, and an instructor configured to instruct an operation of the plant on the basis of the operation parameter determined.
