The objective of this study was to investigate the differences in postural changes during typing tasks with and without a recently developed integrated backrest and seat cushion. A total of 30 healthy individuals (27 males, 3 females; mean age of 24 ±1.96) participated in this study. Participants performed typing tasks for 30 minutes while sitting on a regular chair and a backrest chair with a lumbar support device installed. Video analysis was used to observe postural changes, and independent t-tests and paired t-tests were used to verify the statistical significance of the mean difference in postural change angles. The statistical significance level was set at p<.05. The pre-post changes in pelvic angle in the control group significantly decreased (p<.001). The pre-post changes in trunk flexion angle in the control group significantly decreased (p<.05). The pre-post changes in vertical distance in the control group significantly increased (p<.05). The pre-post changes in hip flexion angle in the group using a lumbar support device significantly decreased (p<.001). The pre-angle of hip flexion between the group using a lumbar support device and the control group was significantly different (p<.05). The post-angle of pelvic and trunk flexion were significantly different between the group using a lumbar support device and the control group (p<.05). The use of a lumbar support device effectively maintains the lordotic curvature of the lumbar spine during seated work. further research and development of support devices and chairs for modern individuals who spend extended periods of time sitting should continue to be pursued.