An operation rule determination device includes an environment execution unit that obtains a state of a control target after each operation and the degree associated with the state for a series of operations on the control target, by using degree information in which the state and the degree of desirability of the state are associated with each other, and a risk-considered history generation unit that calculates a cumulative degree obtained by accumulating the obtained degree for the series of operations, and, when the cumulative degree satisfies a condition, reduces the degree associated with the state after the series of operations in the degree information.