Disclosed herein is a hydraulic braking device including: a reservoir for storing hydraulic oil; a hydraulic pressure supply unit for sucking hydraulic oil from the reservoir and supplying braking pressure to a wheel cylinder; a main flow path for supplying the braking pressure of the hydraulic pressure supply unit to the wheel cylinder; a pressurizing valve for opening/closing the main flow path; a master cylinder for generating braking pressure; a sub flow path for supplying the braking pressure of the master cylinder to the main flow path; a shutoff valve for opening/closing the sub flow path; and a controller for detecting the pressure of the main flow path in a state where both of the shutoff valve and the pressurizing valve are closed, and determining that a leak occurred in the pressurizing valve when the detected pressure is higher than a preset value.