Acute eosinophilic pneumonia is characterized by acute febrile disease with diffuse interstitial infiltration on chest radiography, eosinophilic infiltration of lung parenchyma on lung biopsy and good response at corticosteroid therapy. There has been several reports that support cigarette smoking recently, even though the pathogenesis is not clear. We encountered a case of acute eosinophilic pneumonia induced by cigarette smoking, who, being a 20-year-old man, presented with acute onset of fever after his first cigarette smoking. His clinical symptoms and the infiltrations on onset x-ray improved after a treatment with corticosteroid.