A nine-year-old girl with mental retardation accidentally swallowed an axle of a toy car and was urgently hospitalized with the diagnosis of left bronchial foreign body. While various monitors were installed and removal of the foreign body by a ventilating rigid bronchoscope was in preparation, the patient suddenly coughed and vomited, with the foreign body found in the vomit. When examining infant cases of air way foreign body, attention tends to be focused on the diagnosis and treatment. However, patients are at risk of aggravating difficulty in breathing or suffocation as long as foreign bodies are present in the air way. It is important to monitor carefully for changes in the breathing and to prepare for unexpected events.