This paper presents a proximity sensor for recognizing an object in 360º all around with response time only 1[ms]. The sensor applies unique design of analog net-structure circuit, which enables all-face mounting on various peripheries, fast-response, and simplification of information processing. Thus, the sensor is especially available for avoiding sudden contact with rapidly approaching objects for mobile robots, robot arms, robot hands, and other robotic systems. In this paper, the structure and detecting principle of the sensor are firstly described, then, its detection property is tested by experiments. The result shows that the sensor recognizes the angle of the nearby object with accuracy of 3[deg]. Furthermore, as practical use of the sensor, a large size model is produced for a mobile robot to achieve omni-directional sensing. By using the application model, two detection methods are discussed on situations where the number or the position of objects differs.