Amikacin is an effective antibiotic for NTM infection. However, intravenous amikacin treatment is limited by its systemic route of administration and a lot of adverse events. Amikacin inhalation treatment could overcome these limitations and also could be effective for treatment of NTM pulmonary disease due to maintaining a high lung concentration. The purpose of this study is to determine whether amikacin inhalation treatment is effective in patients with MAC infection who experienced treatment failure after standard treatment for more than 6 months or with M. abscessus infection.