A 67-year-old man diagnosed with small cell lung cancer was managed with amrubicin as second-line treatment. He visited the emergency department because of fever, right-sided chest pain, and hemoptysis on the 14th day of treatment. He developed respiratory failure and shock. Laboratory studies showed severe neutropenia, and a chest X-ray image revealed right-sided lung infiltration. He received left-sided bronchial intubation and intensive care. He subsequently died on the same day. Autopsy specimens showed diffuse bilateral lung necrosis and invasion of Gram-positive rod-shaped microorganisms. Bacillus cereus was later isolated from the blood cultures. We concluded that the diagnosis was B. cereus necrotizing hemorrhagic pneumonia. B. cereus can cause fatal infections. Therefore, infection due to B. cereus should be considered in cases of chemotherapy-related febrile neutropenia.