In recent years, it has been reported that the dynamics and sensibilities of passengers differ from a driver. However, there has been little research on the control of suspension that takes into consideration the dynamics of the human body and its sitting position. In this paper, semi-active suspension control is developed to reduce passenger’s vibration and motion. First, a vehicle and passenger model including the dynamics of human body and the sitting position is constructed. Second, robust control system design method which uses the vertical acceleration of a passenger’s head as one of the controlled output, is proposed. In order to control the jerk which is generated by changing of a damping coefficient rapidly, the robust controller is designed based on the Lissajous figure of damping force. From the result, it was confirmed that at nearly the resonance frequency of the vertical direction of the passenger’s head, the proposed control method can reduce the passenger's vibration better than general methods of control that use a vertical acceleration of the vehicle body as one of the controlled output.