Creative activities, such as painting and music, are one source of satisfaction and fulfillment for people with disabilities. However, some individuals with disabilities cannot satisfactorily enjoy such activities due to involuntary movement. In this study, we developed a drawing assist system and prevention control of error-drawing for nonperiodic involuntary movements. Drawing assist system has position correction filter to attenuate involuntary movement on the basis of characteristics of it. It is suggested that error-drawing is caused by imbalance in involved muscles. Prevention control of error-drawing is based on impedance control and suppresses involuntary movements. Our system enabled drawing based on the participant's own senses and motor control, even when experiencing involuntary movement.