A hydraulically-controlled disk brake including a hydraulically-actuated parking brake, which includes: - a brake caliper which includes a casing in which at least one primary hydraulic cavity is formed, which is open axially forward; - at least one primary piston which is sealingly axially slidingly mounted in the primary hydraulic cavity of the casing, which is axially backward delimited by a bottom transverse wall of the casing and in which the primary piston axially delimits a primary hydraulic chamber, the primary piston being able to cooperate with an associated pad of disk brake; - a piston rod which is axially movable with the primary piston, which is rotatably immobilised relative to the casing, which sealingly passes through the bottom transverse wall, and which includes a threaded segment; - a wheel for axially blocking the piston rod, which is mounted reversibly screwed on the threaded segment of the piston rod so as to be axially movable relative to the piston rod, backward by screwing or forward by unscrewing; - a controlled motor able to drive the blocking wheel to rotate; - an axial stop transverse plate which is axially fixed relative to the casing and which includes a forward stop transverse face, the blocking wheel being axially movable, relative to the piston rod, between a stop forward position and a stop backward position in which the blocking wheel axially bears backward against said forward stop transverse face; - an intermediate cavity which is axially arranged at the back of the primary hydraulic cavity, and which is delimited: -- axially forward by the bottom transverse wall, and axially backward by the stop transverse plate; -- and radially by an intermediate tubular body which is joined to a back axial end of the casing; - and a back cover which is joined to a back axial end of the tubular body and in which a secondary hydraulic cavity is formed, which is axially forward delimited by the stop transverse plate; a brake in which the piston rod includes: --- a back end segment which axially extends backward beyond the stop transverse plate and which is radially centred relative to the cover; --- a rotation blocking segment which axially extends through the stop transverse plate; --- and a front end segment which axially extends through the bottom transverse wall and which is radially centred relative to this bottom transverse wall; characterised in that the stop transverse plate is in the general shape of a disk a peripheral portion of which is mounted axially clamped between two facing portions (71, 76) of the back end of the tubular body and of the front end of the cover, respectively. - a brake caliper which includes a casing in which at least one primary hydraulic cavity is formed, which is open axially forward; - at least one primary piston which is sealingly axially slidingly mounted in the primary hydraulic cavity of the casing, which is axially backward delimited by a bottom transverse wall of the casing and in which the primary piston axially delimits a primary hydraulic chamber, the primary piston being able to cooperate with an associated pad of disk brake; - a piston rod which is axially movable with the primary piston, which is rotatably immobilised relative to the casing, which sealingly passes through the bottom transverse wall, and which includes a threaded segment; - a wheel for axially blocking the piston rod, which is mounted reversibly screwed on the threaded segment of the piston rod so as to be axially movable relative to the piston rod, backward by screwing or forward by unscrewing; - a controlled motor able to drive the blocking wheel to rotate; - an axial stop transverse plate which is axially fixed relative to the casing and which includes a forward stop transverse face, the blocking wheel being axially movable, relative to the piston rod, between a stop forward position and a stop backward position in which the blocking wheel axially bears backward against said forward stop transverse face; - an intermediate cavity which is axially arranged at the back of the primary hydraulic cavity, and which is delimited: -- axially forward by the bottom transverse wall, and axially backward by the stop transverse plate; -- and radially by an intermediate tubular body which is joined to a back axial end of the casing; -- axially forward by the bottom transverse wall, and axially backward by the stop transverse plate; -- and radially by an intermediate tubular body which is joined to a back axial end of the casing; - and a back cover which is joined to a back axial end of the tubular body and in which a secondary hydraulic cavity is formed, which is axially forward delimited by the stop transverse plate; --- a back end segment which axially extends backward beyond the stop transverse plate and which is radially centred relative to the cover; --- a rotation blocking segment which axially extends through the stop transverse plate; --- and a front end segment which axially extends through the bottom transverse wall and which is radially centred relative to this bottom transverse wall;