A Hunter syndrome therapeutic agent contains a first composition to be intravenously injected and a second composition to be subcutaneously injected. The agent can reduce the number of visits to the hospital by patients with Hunter syndrome to twice a month or less. It maintains a medicinal effect equivalent to or greater than that of a conventional once-a-week IV injection, increases drug-taking compliance of patients in comparison to conventional therapeutic agents and treatment methods, and enables enhanced patient welfare and convenience.