A 43-year-old man was admitted to our hospital because of productive cough and an abnormal chest radiograph. He had smoked one pack of cigarettes per day for 23 years. Chest radiograph on admission showed diffuse reticulo-linear infiltrates, most prominent in both upper lung fields. Chest HRCT scan showed multiple micronodules, cavitated nodules, and thick-walled cysts with ground-glass attenuation. These radiographic findings suggested pulmonary eosinophilic granuloma (PEG). Histological findings of the biopsy specimen obtained from video-assisted thoracoscopy demonstrated granulomatous lesions consisting of S-100 protein-positive Langerhans cells with infiltration of eosinophils and fibrous lesions (starfish-like fibrosis). A definitive diagnosis of PEG was made, and he immediately ceased smoking. The symptoms and radiographic findings markedly improved within 3 months after cessation of smoking. Chest HRCT on the final scan revealed that nodules and almost all cystic lesions vanished. He resumed smoking without any sign of recurrence.