Simultaneous EMG recording of the laryngeal abductor (PCA) and adductor (INT) muscles with laryngeal filming by use of a fiberscope was made with two subjects during utterances of various voiceless sounds and sound sequences in Japanese words in a frame sentence. For each of the utterance samples, the activity patterns of the two muscles were observed in correspondence with the opening and closing movements of the glottis. There was a reciprocal pattern of activity between the two muscles in relation to glottal abduction and adduction during speech, this finding being consistent with previous reports. There was, however, a difference between the subjects in that the time course of the glottal movements was predominantly controlled by the PCA in one subject, while the INT as well as the PCA appeared to actively control the glottal condition in the other subject. [Work supported by Ministry of Education Grant‐in‐Aid for Scientific Research, No. 239005.]