A double cup-shaped piston for a disc brake including an electromechanical parking brake device. An aspect of the invention permits an improved compromise between easier operability, rationalized component logistics in piston production, reduced hydraulic volume uptake in cooperation with the wheel brake periphery, and enhanced fatigue strength under maximum collective stress, in particular for heavy-duty applications of a disc brake with an electromechanical parking brake device. The problem is solved by the presence of a piston wall, which is provided, on the one hand, to sit with a free edge on a rear plate of a friction lining, and wherein the piston, on the other hand, includes an integral dome which forms an open receptacle for an actuator arranged diametrically to the edge of the piston.