In rapidly aging society of recent year, music therapy has been focused as one of the occupational therapy of the day care. However, there is a possibility with the weakness for some people to acquire rhythm. Therefore, it is necessary to support these kinds of people in music therapy situation of the day care. In this study, based on visual induced postural sway which is one of the illusions, a supporting method with visually presented coordinated rhythm has been proposed. Through the experiments with subjects, relationship between the weakness to acquire rhythm and postural sway has been confirmed. Finally, it is suggested that the easily induction for postural sway by visual stimulation is achieved in the situation of visual stimulation with multiple people compare with the single subject situation.