Results: Before β2 agonist inhalation, the area under the entire curve (AT) and 99% frequency (F99) in the lung sound of inspiratory flow around 2.0L/s due to slightly strong breathing were significantly higher than the lung sound of inspiratory flow around 1.0L/s due to rest breathing. However, no marked differences were observed in the lung sound parameters based on the lung sound spectrum. The improvement in the lung sound parameters after β2 agonist inhalation was clearer at an inspiratory flow around 1.0L/s than that around 2.0L/s.