A time-delayed automatic shut-off device for a tap, designed to be mounted in a tap body that is provided with a water or fluid inlet, for example axial, and a water or fluid outlet, for example radial, the device comprising: - a chamber formed by two zones (Z1, Z2) separated by a piston where a fluid flows not communicating with a main circuit that is generally water; - a closing member to block, in a closed position of the tap, the passage of the water or other fluid between an inlet and outlet of the tap and to release said passage in an open position of the tap; - a command, in particular made up of a control button and the piston securing said command with the closing member, to cause the tap to go, in an opening movement, from the closed position to the opening position following an intervention by a user; - a spring to cause, by pushing the control button through a closing movement opposite the opening movement, the tap to go from the open position to the closed position; - said chamber (Z1, Z2) being hydraulically hermetic and being crossed through by a control rod and in particular including a second fluid; - a piston including a pierced shoulder and a sealing gasket sliding on the side wall of the hydraulic chamber during the opening movement and the closing movement of said piston, said piston including holes crossing through it parallel to the translational movement of the piston, said holes allowing, during the opening movement of the piston, the passage of the fluid from the first zone to the second zone of the hydraulic chamber; - a flat seal applied on the holes of the piston by the spring to free the passage of the second fluid in at least one of the holes crossing through the piston during the opening movement, and to block the passage of the second fluid in the holes crossing through the piston during the closing movement, in that state only the return passage of the fluid being provided by an orifice at the center of the piston whereof the inlet is situated in the first zone and the outlet in the second zone; - said passage being adjusted by a cone-point set screw; - said control button being pierced by an axial hole making it possible to access the cone-point set screw for adjustment. - a chamber formed by two zones (Z1, Z2) separated by a piston where a fluid flows not communicating with a main circuit that is generally water; - a closing member to block, in a closed position of the tap, the passage of the water or other fluid between an inlet and outlet of the tap and to release said passage in an open position of the tap; - a command, in particular made up of a control button and the piston securing said command with the closing member, to cause the tap to go, in an opening movement, from the closed position to the opening position following an intervention by a user; - a spring to cause, by pushing the control button through a closing movement opposite the opening movement, the tap to go from the open position to the closed position; - said chamber (Z1, Z2) being hydraulically hermetic and being crossed through by a control rod and in particular including a second fluid; - a piston including a pierced shoulder and a sealing gasket sliding on the side wall of the hydraulic chamber during the opening movement and the closing movement of said piston, said piston including holes crossing through it parallel to the translational movement of the piston, said holes allowing, during the opening movement of the piston, the passage of the fluid from the first zone to the second zone of the hydraulic chamber; - a flat seal applied on the holes of the piston by the spring to free the passage of the second fluid in at least one of the holes crossing through the piston during the opening movement, and to block the passage of the second fluid in the holes crossing through the piston during the closing movement, in that state only the return passage of the fluid being provided by an orifice at the center of the piston whereof the inlet is situated in the first zone and the outlet in the second zone; - said passage being adjusted by a cone-point set screw; - said control button being pierced by an axial hole making it possible to access the cone-point set screw for adjustment.