1. A calculating device comprising: a memory apparatus that stores an action set including a plurality of actions and a state set including a plurality of states corresponding to the actions included in the action set; and a processor configured to: select an action from the action set and select from the state set, a state that corresponds to the selected action; acquire an evaluation value by evaluating the combination of the selected action and the selected state; identify for each selected action, a lowest evaluation value that is lowest among acquired evaluation values; determine the lowest evaluation value among evaluation values of all the states selected for each action as a minimax candidate, and determine, as a minimax, an evaluation value that is highest among the lowest evaluation values corresponding to the actions; at each time an evaluation value is acquired for a combination of a state and an action after the minimax candidate is determined, compare the acquired evaluation value and the minimax candidate, and terminate selection of a state corresponding to the action when the evaluation value is lower than the minimax candidate and to select an action from unselected actions included in the action set; and output an action corresponding to the determined minimax.