Bronchocentric granulomatosis in asthmatic patients has been generally considered to be associated with allergic bronchopulmonary aspergillosis and represent a histopathologic manifestation of fungal hypersensitivity. Here we report a case of an idiopathic bronchocentric granulomatosis in a 17-year-old man with a history of asthma. He was admitted to the hospital with a fever and cough, and a chest CT scan showed peribronchial consolidation in the pulmonary parenchyma, which was unresponsive to antibiotic therapy. The pathological findings obtained by video-assisted thoracoscopic lung biopsy revealed necrotizing granulomatous inflammation centered on bronchi and bronchioles and there was no evidence of fungal colonization, resulting in a diagnosis of idiopathic bronchocentric granulomatosis. Systemic corticosteroid therapy led to clinical and radiological recovery. Physicians should take into account the possibility of the idiopathic process in bronchocentric granulomatosis of asthmatic patients.