A self-propelling apparatus for a vacuum cleaner in which a cleaner body is pivotably mounted to a brush assembly is provided. The self-propelling apparatus includes a sensor unit having a wheel part that pivots in the opposite direction to a moving direction of the vacuum cleaner, a connection part connected with the wheel part and fixed to the brush assembly by one end thereof and a switch part turned on and off according to the connection part, and generating progression and retrogression signals according to pivoting motion of the wheel part, and an interception unit generating an interception signal when the cleaner body is in an upright posture, and a driving unit moving the vacuum cleaner in accordance with the progression and retrogression signals.