Previous studies have reported that spatiotemporal stability in human rhythmic movements increases when entrained to rhythmic auditory stimuli (RAS), such as music and metronome beats. RAS can be produced not only by external devices but also vocalization. Therefore, it is possible that a variety of rhythmic movements can be stabilized with vocalization. In our previous studies, we have revealed that the stabilization effect of vocalization on whole-body movement. This effect can be caused by a voice as RAS and/or vocalization as movement. Here we explored whether the stability of whole-body movement can be enhanced by vocalization without auditory feedback. If the stabilization effect doesn't occur without auditory feedback, it is possible to interpret that the stabilization effect is caused by voice as RAS. Auditory feedback was blocked by white noise delivered to the participant through a headphone. Participants performed rhythmic knee-flexing movement in a standing posture in three conditions: knee flexion with vocalization "Ta" (coordination condition), knee flexion with vocalization without auditory feedback (coordination-inaudible condition), and knee flexion without vocalization (control condition). We compared variability in knee movement interval among three conditions. Results showed that variability in knee movement in the coordination and coordination-inaudible condition was smaller than in the control condition, p < .01 and p < .05, respectively. There was no significant difference in knee-movement interval between the coordination and coordination-inaudible conditions. Overall, the present study revealed stabilization effect of vocalization on whole-body movement occurs even without auditory feedback. These findings suggest that the stabilization effect can be caused under a common coordination principle applicable to multiple combinations among movements of limbs and other body parts such as vocalization organs.