It is well-known that the malignant external otitis is commonly occurred in elderly diabetes patients. In spite of local treatment, the lesion may be frequently progressive and may reach to the necrosis of the cartilage, the granulation formation, the facial nerve palsy, and the meningitis. Seventy-two-year old woman was transferred to our clinic. She had the abscess and the necrosis of the left auricle and the external auditory canal. Pseudomonas aeruginosa was identified in the bacterial culture of extracted pus from the necrotic tissue of the auricle. She had no underlying chronic disease such as diabetes melitus. However, acute myelocytic leukemia(AML) was confirmed through the bone marrow aspiration and biopsy.