A suction drill unit for the installation of a drill dowel (2) into rock, concrete, masonry and similar materials has an insertion end (3) for insertion into an at least partially rotary and percussive acting hand tool drilling device, with a reduced diameter shank (7) having an open suction passageway (9) extending axially through the shank (7) towards a bit head (8) and a rearward radial communication passage (10) connected thereto for suction-tight communication with a non-rotary suction head (11), wherein the drill bit head (8) is formed with an eccentrically arranged bit head tip (12) for boring of a hole (14) having a diameter (D) greater than that of the drill bit head diameter (B).