A ring binder includes at least two first and second pipes which are hollow inside; a first ring positioned at an end of the first pipe to be opened and closed; a second ring positioned between the first pipe and the second pipe to be opened and closed; a third ring positioned at an end of the second pipe to be opened and closed; and a support bar passing through the first and second pipes and the first through third rings and holding the first and third rings so that the first and third rings are not separated from the first and second pipes, wherein ends of first, second, and third stationary half rings are combined with and separated from ends of first, second, and third rotating half rings.