Abstract: An energy operation support device includes: an optimization calculation unit; and operation guideline transmission units. The calculation unit sets an operation condition of an energy facility as a determination variable based on information obtained from a result value/prediction value acquisition unit, unit price information acquisition unit, and functioning information acquisition unit, constitutes a balance condition of an energy utility, and adds a shortage amount determination variable of the energy utility to the generation variable side of the balance condition and establishes a constraint condition. Then, the unit sets an objective function containing the total cost for the energy operation of a steel works and the shortage amount determination variable and arithmetically operates the determination variable so the objective function asymptotically approaches the optimum value to satisfy the constraint condition.