The function of the clutch booster is to reduce labor intensity of the driver in clutch operation. When the vehicle is started, the driver steps on the clutch pedal with the pedal force transmitted to the clutch booster through the hydraulic output of the clutch master cylinder. Through the amplifying effect of the clutch booster, a higher hydraulic output is transmitted to the clutch slave cylinder. The clutch release fork separates the clutch pressure plate assembly and clutch disc assembly from the flywheel. It is at this time that the driver can perform gear shift to complete the start of the vehicle.