We succeeded in recording action potentials from the bronchial smooth muscles in 10 healthy males and 20 cases of bronchial asthma by means of the new electrode described by us in the preceding paper (Akasaka et al. 1975). From these electromyographic studies, we presented the direct evidence of spasm of the bronchial smooth muscles as one of the etiological factors responsible for the airway narrowing in asthmatic attack.