Hydraulic master cylinder for vehicle with bar handle

A hydraulic master cylinder (1) for a vehicle having a bar handle has a hydraulic master cylinder (2) including a cylinder bore (10) opening toward a front part of a vehicle body and a piston (11) inserted into the cylinder bore (10), the hydraulic chamber (13) being defined between the piston (11) and a bottom of the cylinder bore (10) and the hydraulic master cylinder (2) being mounted on a handle bar (7) of the vehicle so as to be oriented in a longitudinal direction of the vehicle body; and an operation lever (3) for pressing the piston (11) toward a bottom of the cylinder bore (10) by gripping and operating the operation lever (3) toward a grip of handle bar (7), the operation lever (3) being pivotally supported at a lever mounting part (5b) of the hydraulic master cylinder (2), wherein a handle bar mounting part (5a,b) of the hydraulic master cylinder (2) is offset to a position closer to the grip than a center axis of the cylinder (2).