A coordinate detecting device to be used in an electronic information board system including a display section including a display surface with which a target to be detected is in contact and a frame having four sides surrounding the display surface, two optical sensor units (360, 370) disposed at respective ends of one side of the display section and including respective light emitting and receiving surfaces to irradiate and receive light, and optical reflection members (320, 330, 340) disposed at respective other three sides of the display section, wherein a coordinate position where the target to be detected is in contact with the display surface is detected based on a reflection of light which is irradiated and received by the optical sensor units (360, 370) and reflected from the optical reflection members (320, 330, 340), the coordinate detecting device comprising: adjustment units (400, 400A) provided in respective corner parts of the coordinate detection device and configured to adjust the respective light emitting and receiving surfaces of the optical sensor units (360, 370) where the reflection light is irradiated and received, and impact absorption units configured to absorb impact applied to the respective optical sensor units (360, 370), wherein the optical sensor units (360, 370) include respective light emitting and receiving sensors (300, 310) to irradiate and receive light to and from the optical reflection members (320, 330, 340), respective print boards on which the light emitting and receiving sensors (300, 310) are mounted and having base ends fastened to the frame of the display section, and respective brackets fastened to a rear surface of the print boards, characterized in that the adjustment units (400, 400A) include respective first adjustment screw members configured to adjust respective distances between the frame and the brackets in diagonal direction, relative to the optical sensor units (360, 370) and the display section, and respective second adjustment screw members configured to adjust respective distances between the frame and the brackets in horizontal direction, relative to the optical sensor units (360, 370) and the display section, and wherein the adjustment units (400, 400A) are configured to adjust the respective light emitting and receiving surfaces by adjusting height positions of light receiving patterns of the received reflection light based on screwed amounts of the first adjustment screw members and by adjusting inclinations of irradiation patterns of the reflection light based on screwed amounts of the second adjustment screw members. adjustment units (400, 400A) provided in respective corner parts of the coordinate detection device and configured to adjust the respective light emitting and receiving surfaces of the optical sensor units (360, 370) where the reflection light is irradiated and received, and impact absorption units configured to absorb impact applied to the respective optical sensor units (360, 370), wherein the optical sensor units (360, 370) include respective light emitting and receiving sensors (300, 310) to irradiate and receive light to and from the optical reflection members (320, 330, 340), respective print boards on which the light emitting and receiving sensors (300, 310) are mounted and having base ends fastened to the frame of the display section, and respective brackets fastened to a rear surface of the print boards, characterized in that respective light emitting and receiving sensors (300, 310) to irradiate and receive light to and from the optical reflection members (320, 330, 340), respective print boards on which the light emitting and receiving sensors (300, 310) are mounted and having base ends fastened to the frame of the display section, and respective brackets fastened to a rear surface of the print boards, characterized in that the adjustment units (400, 400A) include respective first adjustment screw members configured to adjust respective distances between the frame and the brackets in diagonal direction, relative to the optical sensor units (360, 370) and the display section, and respective second adjustment screw members configured to adjust respective distances between the frame and the brackets in horizontal direction, relative to the optical sensor units (360, 370) and the display section, and wherein the adjustment units (400, 400A) are configured to adjust the respective light emitting and receiving surfaces by adjusting height positions of light receiving patterns of the received reflection light based on screwed amounts of the first adjustment screw members and by adjusting inclinations of irradiation patterns of the reflection light based on screwed amounts of the second adjustment screw members. respective first adjustment screw members configured to adjust respective distances between the frame and the brackets in diagonal direction, relative to the optical sensor units (360, 370) and the display section, and respective second adjustment screw members configured to adjust respective distances between the frame and the brackets in horizontal direction, relative to the optical sensor units (360, 370) and the display section, and wherein the adjustment units (400, 400A) are configured to adjust the respective light emitting and receiving surfaces by adjusting height positions of light receiving patterns of the received reflection light based on screwed amounts of the first adjustment screw members and by adjusting inclinations of irradiation patterns of the reflection light based on screwed amounts of the second adjustment screw members.