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

[Problem] To more smoothly commence actuation of a stroke simulation function. [Means for Resolution] A pedal feel simulator unit 3 of a master cylinder 1 has a start-up load reducing unit 28, and this start-up load reducing unit 28 has a start-up load reducing spring 29. The elastic modulus of the start-up load reducing spring 29 is set smaller than the elastic modulus of a simulator actuation piston return spring 16. Consequently, when the start-up load reducing spring 29 is pressed by an input shaft 4, the start-up load reducing spring 29 starts to elastically flex before the simulator actuation piston return spring 16 elastically flexes and a simulator actuation piston 14 starts to move forward. Because of this, the start-up load of the pedal feel simulator unit 3 is reduced.