Disclosed is an automatic door closure unit which is simple in structure and thus enables easy processing, and which has an independent hydraulic circuit to ensure operating stability. The automatic door closure unit comprises: a cylindrical main housing; a damper housing dividing the main housing into an upper chamber and a lower chamber, the interior of which is filled with oil and which has a fixed vane protruding toward the center thereof; a cover fixed onto an upper surface of the main housing; a rotatable shaft, one end of which extends outwardly through the cover and is rotatably supported, and the other end of which extends through the damper housing and is rotatably supported at a bottom surface of the main housing; a rotatable vane integrally formed with an outer surface of the rotatable shaft so as to cooperate with the fixed vane in order to divide the interior of the damper housing into a first chamber and a second chamber; a return spring which provides restoring force for returning the rotatable shaft to an initial set position during a door-closing operation; and a damping means for selectively providing a damping function when the rotatable shaft and the rotatable vane rotate in the door closing direction.