A control parameter tuning device for tuning a control parameter stored in a control system that controls a controlled object on the basis of a control parameter, includes a model updating module configured to update a controlled-object model that represents the controlled object when tuning a control parameter using data acquired when the controlled object operates; a first search module configured to repeatedly run simulations using the updated controlled-object model to search for a control parameter within a first range, and output a candidate for an optimal value for the control parameter; and a second search module configured to repeatedly operate the controlled object and search for a control parameter within a second range narrower than the first range and determined by the candidate output by the first search module and acquire operation results for the controlled object.
