This study was made to examine the hypothesis that verbal hallucination is an expression of so-called “inner speech,” using electromyographic techniques. In 9 schizophrenic patients, it was found that the experience of verbal hallucination was accompanied by an increase of electromyogram (EMG) discharge of the speech musculature in 47.6%. The time lag between the start of increase of EMG discharge and that of verbal hallucination was usually within 1.5 seconds. The duration of the EMG increase was positively correlated with the duration of verbal hallucination. It was further found that the verbal hallucination with an increase of EMG of the speech musculatures was experienced as a relatively loud one by the subjects, while the hallucination without EMG increase was experienced as a small one.It is suggested that subvocal speech, a part of inner speech, is produced at the moment of experiencing verbal hallucinations as demonstrated by the increase of EMG of the speech musculatures.