Orientation and Mobility (O&M) skills are essential for visually impaired people to live an independent life. O&M skills are generally evaluated subjectively by instructors, a quantitative evaluation method is required. Accidents in which visually impaired people become victims at intersections and station platforms have become a social problem. The final purpose of this research is to establish a method to quantitatively evaluate the walking skill proficiency of visually impaired people. We investigated the effectiveness of biological signals using Near-Infrared Spectroscopy (NIRS) for quantitative evaluation of walking skills. In a previous study, we measured brain activity in sighted subjects who wore eye masks. The experimental results showed that brain activity in the prefrontal cortex changed significantly, especially when walking alone through narrow passages. We considered to be due to anxiety and caution caused by being aware of contact with the wall. In this experiment, we added subjects to verify the results of past experiments. In addition, we focused on the distance between the subject and the wall. We considered brain regions involved in cognition and intention, which are important for visually impaired people when walking.