A hydraulic braking system includes: a master cylinder including: a pressurizing piston fluid-tightly and slidably fitted in a housing; a front pressure chamber located in front of the pressurizing piston and connected to a brake cylinder; and a rear chamber located behind the pressurizing piston; a rear-hydraulic-pressure control device connected to the rear chamber of the master cylinder and configured to supply control hydraulic pressure to the rear chamber; and an air bleeding device configured to perform air bleeding for an air bleeding target portion as at least a portion of the rear-hydraulic-pressure control device, in a state in which working fluid is prevented from being supplied to the rear chamber.