We report three cases of multicentric Castleman's disease (MCD) successfully treated with anti-interleukin-6 receptor antibody (tocilizumab). Tocilizumab was administered intravenously at a dose of 8 mg/kg every 2 weeks. In each case, tocilizumab alleviated symptoms, including generalized fatigue, pyrexia, and alleviated biochemical abnormalities, including anemia, hypoalbuminemia, hypergammaglobulinemia, and increased C-reactive protein (CRP). Side effects included hypercholesterolemia, acute pyelonephritis, mild inflammation of the parotid glands, and upper respiratory system inflammation. Other severe side effects were not observed. These results indicate that tocilizumab is effective for the treatment of MCD. This is the first report on tocilizumab efficacy for Castleman's disease after approval for use for Castleman's disease.