To fix an adjusting member in a cylinder hole easily and securely and enables a further miniaturization and cost reduction in a vehicular hydraulic brake device equipped with a pressure regulation valve means.

The vehicular hydraulic brake device is provided with the pressure regulation valve means 30 which introduces a fluid pressure of output power of an auxiliary fluid pressure source to a first pressure regulation chamber C1 formed forwardly of a control piston 20 and regulates a pressure of the first pressure regulation chamber C1 to a predetermined pressure in accordance with a movement of the control piston. The adjusting member 40 is arranged forwardly of the pressure regulation valve means 30 in the cylinder hole 3 and the pressure regulation valve means is fixed in a predetermined position in the cylinder hole. The cylinder hole is sealed to form a second pressure regulation chamber C2 formed forwardly of the adjusting member by a sealing member 50. The first pressure regulation chamber, the second pressure regulation chamber, a pressure regulation valve means and an aiding chamber are communicatingly connected with each other. Preferably a pressure receiving area to the fluid pressure of the second pressure regulation room formed forwardly of the adjusting member is determined to be almost equal to that to the fluid pressure of the first pressure regulation room formed rearwardly of the pressure regulation valve means.

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