Lumbar loading causes increased intervertebral pressure and is an important factor in low back pain. However, it is difficult to quantitatively assess what kinds of actions affect lumbar load and how much the lumbar load changes. Low back pain occurs not only in the workplace but also in activities of daily living, so it is necessary to investigate factors in low back pain by measuring movements at various locations and determining the magnitude of the lumbar load. Lumbar load varies depending on posture and external load. However, each person perceives lumbar loading differently and at different times. It is also known that wearing a pelvic belt can improve posture and reduce lumbar load. Accordingly, in this study, the tightening force of a pelvic belt was measured to determine its effect on posture and lumbar load, and the relationship between perceived burden and lumbar load was evaluated.