A plant control apparatus has a measurement signal DB, an operation signal DB, a numerical value analysis executing unit, a numerical value analysis result DB, a model for estimating a value of a measurement signal for an operation signal, learning unit using the model, a learning information DB, a control logic DB for information used by an operation signal generating unit, a knowledge DB for plant running characteristics, and an analyzing unit processing information in the numerical value analysis result DB by information in the knowledge DB, learning information DB, operation signal DB, and measurement signal DB, wherein the analyzing unit includes at least one of a learning base analyzing unit checking adequacy of an operation method, a signal analyzing unit for evaluating an effect of the operation signal upon the plant and presence/absence of an abnormal signal, and a knowledge DB updating unit correcting information in the knowledge DB.