A braking device for a vehicle is provided which includes a braking simulator, thus resulting in improved mountability of the braking device in the vehicle. The braking device is designed to permit component parts of the hydraulic booster to slide on one another in response to a braking effort on a brake pedal, thereby absorbing an undesirable load on the braking device and also ensuring the stability in operating the brake pedal. This results in improved durability and maneuvering feeling of the braking device.