to image not only the user in front of a camera but also documents situated below , a rail member is vertically attached to a sidewall of a display case , a slide rod fixing clamp is slidably mounted on the rail member , a slide rod is transversely displaceably mounted on the slide rod fixing clamp , an orthogonal rod is secured to slide rod , and a camera mounting clamp is mounted on the orthogonal rod in such a manner that it is rotatable around the orthogonal rod . thus , a camera can be positioned lower than in the instance where it is disposed on top of a display . also , the camera can be directed downward by virtue of the camera mounting clamp .