The present invention provides an agent for inhibiting alveolar airspace enlargement containing adiponectin or an agent for inhibiting alveolar wall destruction containing adiponectin. The pulmonary disease therapeutic agents of the present invention are highly safe drugs that possess an excellent effect of decreasing the deterioration of the pulmonary function, such as airflow limitation, and exhibit an extremely high effect of treating pulmonary disease accompanied by irreversible deterioration in pulmonary function, with fewer adverse side effects such as nausea, vomiting and gastric acid secretion.本發明提供用於抑制肺泡氣室擴張之一種含有脂締素(adiponectin)的藥劑或用於抑制肺泡壁破壞之一種含有脂締素的藥劑。本發明的肺部疾病治療劑係高度安全的藥物，其具有減少肺部功能惡化諸如氣流限制之極佳效用，及在治療伴隨不可逆性肺部功能惡化之肺部疾病方面展現極高的效用，及產生很少的不良副作用諸如噁心，嘔吐及胃酸分泌。
