Abstract: The invention relates to a disc brake having at least one brake disc, at least one friction lining and at least one actuating apparatus, wherein the actuating apparatus comprises at least one actuating piston which is movably housed in a housing of the disc brake and a sealing element having a first sealing surface configured to produce a sealing contact to a contact surface of the housing, and a second sealing surface configured to produce a sealing contact to a contact surface of the actuating piston in order to seal the actuating piston to the housing, wherein at least one of the sealing surfaces comprises a friction surface configured so that it maintains the sealing contact to the contact surface in the case of a movement of the actuating piston relative to the housing and furthermore allows a frictionless movement of the actuating piston relative to the housing.