Human gait function can decrease due to disability or aging. The elderly and persons with disabilities need walking training or assistance using a device, which require appropriate selection of methods for evaluating walking function. This study aimed at continuously measuring human walking motion over long distances. The proposed system moves a measurement device that can estimate human posture to enable to continuous measurements of human walking motion. Therefore, the proposed system consists of a measurement device and sensors or a robot that can measure the travel distance of the measurement device. We proposed two systems for the required applications. A manually moved device, consisting of a color depth sensor and a wheel equipped with a rotary encoder, measured patients with relatively high walking function. We also developed a robot that can automatically track subjects to measure patients with low gait function while the therapist supports the patient. Evaluation experiments on the developed systems confirm 7-9° error in joint angle estimations. Moreover, we find that the developed systems are susceptible to vibration.