STROKE SIMULATOR, MASTER CYLINDER HAVING STROKE SIMULATOR, AND BRAKE SYSTEM USING MASTER CYLINDER

[Problem] To obtain a good pedal feeling by more smoothly commencing actuation of a stroke simulation function and to compactly form a stroke simulator. [Means for Resolution] A pedal feel simulator unit 3 that is a stroke simulator has: an input shaft 4 that performs a stroke as a result of an input being applied thereto; a simulator actuation piston 14 that performs a stroke because of the stroke of the input shaft 4; a simulator actuation hydraulic chamber 15 in which simulator actuation hydraulic pressure that applies a reaction force based on the stroke of the input shaft 4 to the simulator actuation piston 14 is generated by the stroke of the simulator actuation piston 14; and a hydraulic actuation control system 28 that controls the simulator actuation hydraulic pressure on the basis of the stroke of the input shaft 4 by controlling the supply and discharge of hydraulic fluid to and from the simulator actuation hydraulic chamber 15.