The importance on walking for health is growing in elder dominated society. We have been developing a new mobility "Tread-Walk 1 (TW-1)" controlled by walking movement. The device uses active treadmill velocity control, which allows the user to walk on the treadmill at any desired velocity. In this paper, the walking movements on the TW-1 were kinematically analyzed and compared with the walking movements on a traditional constant-velocity treadmill and on flat ground. The results showed that the walking pattern on the TW-1 was somewhat similar to that on a constant-velocity treadmill and on flat ground; however, the flexion angle of the hip joint and the dorsiflexion and plantaflexion angles of the ankle joint during TW-1 walking were larger. It also was shown that the foot applied a stronger kicking force to the belt at toe-off and the foot clearance on the TW-1 was larger than that on the constant-velocity treadmill and on flat ground. Therefore, the walking patterns in the swing and stance phase on the TW-1 are little different. However, the walking movements based on the TW-1 active belt control are valuable from the viewpoints of motion training.