In the research field of the intelligent transportation system (ITS) and the roving robot, the driver-support system auto-recognizing road sings and the robot control system auto-recognizing behavior-indication signs are variously suggested. Both systems use the dynamic image processing to acquire features such as the shape and design of sings. Artificial sings valid for the machine vision are sometimes used for these researches. However, in this study, the general road sings adopted in public roads are used, because machines such as robots and vehicles are supposed to live together in real environments. In this paper, nine kinds of sings one third in size such as "STOP," "NO ENTRY" and "NO PASSAGE" are prepared and then some experiments were carried out to recognize these signs under various kinds of measurement condition.