INPUT DEVICE OF VEHICLE BRAKE SYSTEM

An input device of a vehicle brake system which is downsized and has an improved general versatility in comparison with conventional vehicle brake systems is provided. An input device 14 includes: a master cylinder 34 that produces a fluid pressure in accordance with an input of an operation of a brake operating member 12; and a stroke simulator 64 which is provided side by side with the master cylinder 34 and which applies in a pseudo manner a force counteracting the operation of the brake operating member 12 to the brake operating member 12. The master cylinder 34 and the stroke simulator 64 are formed integrally.