A 46-year-old healthy man developed respiratory distress, night sweats, fever, and weight loss after using electronic cigarettes (e-cigs) for approximately 1 month. He presented to the hospital when the symptoms worsened 2 months after onset. The findings of bronchoalveolar lavage (BAL) fluid examination and the following transbronchial lung biopsy examination led to the diagnosis of acute alveolitis: intra-alveolar fibrosis accompanied with exudate containing abundant lipid-laden macrophages, eosinophils, and neutrophils. Eventually, e-cig-induced acute lung injury was diagnosed. The symptoms were rapidly alleviated upon e-cig use termination and methylprednisolone pulse therapy, and no subsequent recurrence was observed. There have been only a few reported cases of e-cig-induced lung injury. In e-cig users presenting with atypical pneumonia, close examination by BAL and biopsy should be performed to verify the presence or absence of lipid-laden macrophages.