Ultrasonic sensors are very useful for mobile robots because they have the advantage that the systems are simple and are easy to handle. When a mobile robot is navigated using an ultrasonic sensor, the map of the environment should include information about the reflection characteristics of objects. For this purpose, the map using a vector expression is better than a grid map. In this paper, an environment reconstruction method using a vector map is proposed. In this method, the environment is reconstructed from the data obtained by using our novel ultrasonic sensor which can measure the normal direction of walls, and the next sensing point is determined automatically. The experimental results of a map construction using this algorithm are shown. As a result of the experiments, it is found that the measurement of walls is possible using this method and the effectiveness of the planning algorithm for the sensing point is verified.