Vehicle suspension system

A vehicle suspension system comprising a first and the second hydraulic cylinders, and a first and the second pressure regulating cylinders which are constituted to satisfy an equation: (S1/ lambda 1 ) x (a1/A1) = (S2/ lambda 2 ) x (a2/A2), wherein S1 and S2 denote piston travels of the first and the second hydraulic cylinders, a1 and a2 denote effective cross-sectional areas of the pistons of the first and the second hydraulic cylinders, lambda 1 and lambda 2 denote vertical displacement amounts at ground contact points of wheels caused by the piston travels S1 and S2 of the first and the second hydraulic cylinders, and A1 and A2 denote effective cross-sectional areas of the first and the second pressure regulating cylinders.