Approximately 20% of traffic fatalities in United States 2012 were caused by rollover accidents. Mostly injured parts were head, chest, backbone and arms. In order to clarify the injury mechanism of rollover accidents, kinematics of six kinds of Anthropomorphic Test Devices (ATD) and Post Mortem Human Subjects (PMHS) in the rolling compartment, whose body size is 50th percentile male (AM50), were researched by Zhang et al.(2014) using rollover buck testing system. It was clarified from the research that flexibility of the backbone and thoracic vertebra affected to occupant’s kinematics. On the other hand, the kinematics research of body size except AM50 will be needed in order to decrease traffic fatalities. There were few reports about the researches of occupant kinematics using FE models of body sizes except AM50. This paper describes results of occupant kinematics of 95th percentile male (AM95), AM50, and 5th percentile female (AF05), simulated using Total Human Model for Safety Version 4 (hereafter referred to as "THUMS”)(5, 6, 7), when a rolling condition was added to rollover buck FE model that include the cases using a simple rigid seat and a vehicle seat.Main results using a vehicle seat were as follows:Lateral head displacement of AM95 case on the leading side seat was the largest among all cases. Direction of occupant kinematics was changed from inboard to outboard on the leading side, which was not observed on the trailing side in all cases. On the leading side occupants in all the cases, the inertial force by roll angular acceleration was dominant from roll angle 0 deg to 30 deg, and after 30 deg, the inertial force by roll angular velocity became dominant. Shoulder belt inclination angle at the side view, relationship between center of gravity(COG) of human upper body and front end of seat side support in the anteroposterior direction and the differences in restraint force which originated from different seat type were discussed.