To examine the several changes in the mental workload during the visual inspection, taking into account several factors like postures such as standing, sitting, and sit-stand as well as shift work involving A shift, B shift, and C shift. The dominant of this study is to appraise, contrast, and compare the mental workload on the combined effects of ergonomic factors, involving postures and shift works of visual inspection workers in the automotive manufacturing industry. The sample size was n = 10, and NASA TLX, a subjective approach, was employed to measure the perceived mental workload. Six workload types are included in the scale: mental demand, physical demand, temporal, performance, effort, and frustration. The findings show that shift work and postures together significantly impact visual inspectors’ mental workload, accounting for 06.83% of the total. Individual factors such as posture, which contributes 32.70%, and shift work, which contributes 11.33%, also significantly impact mental workload. Since individual factor posture contributes highly to the mental workload of visual inspectors, work postures should be notably directed at enhancing mental health and well-being. The optimum mental workload is obtained in the “A” Shift with sit-stand posture. In the future, it would be beneficial to examine a variety of ergonomic aspects to determine the ideal mental workload for visual inspectors.