Disc brake with automatic slack adjuster

The invention concerns a disc brake with an automatic adjusting device, wherein a nut (12) connected to a coupling element (13) is screwed onto an axially displaceable, rotationally rigid spindle (11). An auxiliary piston (32) is displaceably mounted in a bore (31) in the brake piston (4) and connected to the nut (12) by an axially engageable snap-action connection (35, 37, 38).