A generalization hierarchy set generation apparatus comprising: a first generation part that generates a first generalization hierarchy set that is a subset of a generalization hierarchy set from a generalization target data set containing generalization target data as elements and the generalization hierarchy set containing generalization hierarchies as elements, such that the generalization hierarchy set contains a generalization hierarchy including any of the generalization target data included in the generalization target data set as at least one element; and a second generation part that generates a second generalization hierarchy set from the generalization target data set and the first generalization hierarchy set, wherein provided that M is an integer equal to or greater than 1 that expresses a maximum value of a length of the generalization hierarchies included in the generalization hierarchy set, the first generalization hierarchy set satisfies a property such that any generalization hierarchy included in the first generalization hierarchy set includes at least one of the generalization target data included in the generalization target data set, for d that satisfies 0 ≤ d ≤ D-1, where D is a predetermined integer equal to or greater than 1 and less than or equal to M, the first generalization hierarchy set satisfies a property such that data in a dth layer of generalization hierarchies included in the first generalization hierarchy set is the same data, and a set that contains data from a (D-1)th layer to an (M-1)th layer of the generalization hierarchies included in the first generalization hierarchy set as elements includes the generalization target data set, and provided that D' is a predetermined integer equal to or greater than D and less than or equal to M, the second generalization hierarchy set satisfies a property such that a length of generalization hierarchies included in the second generalization hierarchy set is D', and data in a (D'-1)th layer of the generalization hierarchies included in the second generalization hierarchy set is an element of the generalization target data set. a first generation part that generates a first generalization hierarchy set that is a subset of a generalization hierarchy set from a generalization target data set containing generalization target data as elements and the generalization hierarchy set containing generalization hierarchies as elements, such that the generalization hierarchy set contains a generalization hierarchy including any of the generalization target data included in the generalization target data set as at least one element; and a second generation part that generates a second generalization hierarchy set from the generalization target data set and the first generalization hierarchy set, wherein provided that M is an integer equal to or greater than 1 that expresses a maximum value of a length of the generalization hierarchies included in the generalization hierarchy set, the first generalization hierarchy set satisfies a property such that any generalization hierarchy included in the first generalization hierarchy set includes at least one of the generalization target data included in the generalization target data set, for d that satisfies 0 ≤ d ≤ D-1, where D is a predetermined integer equal to or greater than 1 and less than or equal to M, the first generalization hierarchy set satisfies a property such that data in a dth layer of generalization hierarchies included in the first generalization hierarchy set is the same data, and a set that contains data from a (D-1)th layer to an (M-1)th layer of the generalization hierarchies included in the first generalization hierarchy set as elements includes the generalization target data set, and provided that D' is a predetermined integer equal to or greater than D and less than or equal to M, the second generalization hierarchy set satisfies a property such that a length of generalization hierarchies included in the second generalization hierarchy set is D', and data in a (D'-1)th layer of the generalization hierarchies included in the second generalization hierarchy set is an element of the generalization target data set.