A method, medium, and apparatus of a self-propelled mobile unit with obstacle avoidance during wall-following. In the self-propelled mobile unit, a carrying unit may move the mobile unit by using a transmitted power, and a sensor unit can detect an obstacle and a wall, which may be respectively placed in front of and to the side of the mobile unit, with respect to a moving direction of the carrying unit. A controller may direct the carrying unit by generating a path along which the carrying unit moves according to a detection result from the sensor unit. Accordingly, the controller can direct the carrying unit to move while maintaining a predetermined distance (within a predetermined range) from the wall. If the sensor unit detects an obstacle, the controller directs the carrying unit to move in an obstacle free direction.