A method for generating an obstacle map is provided. The method includes: receiving an environment map; generating a binary map indicating a position of an obstacle by a value of an obstacle cost corresponding to a probability of presence of the obstacle at the position, based on obstacle information obtained from the environment map; and generating an obstacle map by applying an obstacle expansion model to the binary map, wherein the applying the obstacle expansion model comprises setting a plurality of obstacle costs of a plurality of neighboring positions of the position of the obstacle in the binary map to a plurality of values, respectively. Accordingly, a safer and stable route can be generated to avoid the obstacle.