A 6-year-old boy with acute lymphoblastic leukemia developed disseminated mucormycosis caused by Rhizopus microsporus during induction therapy. Despite the presence of intestinal perforation and the formation of multiple abscesses, surgical resection and intravenous administration of liposomal amphotericin B were effective, and the patient recovered. Because the prognosis of mucormycosis is very poor, early diagnosis and treatment are important. In cases of patients with risk factors for mucormycosis, physicians must consider the possibility of mucormycosis. Moreover, the empirical administration of liposomal amphotericin B could be a good treatment option before a definitive diagnosis of mucormycosis is made.