Recently, telework or online education due to digitalization acceleration is increased, but reported that many employees such as over 80% feel their faulty posture. Poor posture has effects on productivity, physical disorders, and other body risks. The LaLaCo Chair can provide sitting posture improvement benefits relatively safely even for users. However, these effects are limited to the impressions of each user. In this study, we quantitatively analyzed the cervical vertebra angle using a flexible goniometer when using the LaLaCo Chair. Ten healthy subjects participated in this experiment, and these subjects were measured and analyzed sitting posture after watching a video at 5 minutes, and before and after exercise. The condition that exercise was set to 10, 20 and 30 times at this time. As a result, the posture improvement effect of the LaLaCo Chair on the cervical vertebra angle was over 70% on each exercise condition. Also, the improvement when 10 times of exercise is the highest at 86%. In the future, we plan to analyze the improvement of sitting posture in other working conditions such as using smartphones, personal computers and others.