A rubber vulcanizer includes: a pair of heat plates disposed to be opposed to each other in a prescribed direction and to be apart from each other in the prescribed direction; and one or more dies for rubber molding stacked on each other in the prescribed direction between the heat plates. The rubber vulcanizer is able to realize either a state in which the dies of which the number is N are stacked on each other in the prescribed direction between the heat plates, or a state in which the dies of which the number is (N+1) are stacked on each other in the prescribed direction between the heat plates, where N is a natural number that satisfies at least a condition that 1≦N≦M, and M is a certain positive integer.