Brake actuator unit and electromechanical brake

A brake actuator unit for an electromechanical disc brake, comprising a brake housing, a spindle, a brake piston, which is drive-coupled to the spindle and is axially movable by the spindle, and an axial spindle bearing, which receives the spindle and absorbs the axial reaction forces of the spindle when the brake is applied, wherein the brake housing has a brake calliper having a pad support portion and a pot-shaped brake piston bearing portion, which is integrally connected to the pad support portion and has an axially extending circumferential wall and a bottom, which extends radially inwards from the circumferential wall and through which the spindle runs, wherein, when the brake is operated, the spindle bearing is supported axially on the bottom, and the circumferential wall forms, on its radial inner side, a sliding guide face for the brake piston so that the brake piston bears at least in some portions against the inner side.