It is strongly desired to clarify performances of hydrostatic bearings under mixed lubrication conditions because seldom there is information available on them. Therefore, in a previous paper, we calculated the performances of friction, leakage flow rate and power losses under conditions ranging from mixed to fluid film lubrication and clarified numerically the effects of surface roughness, the eccentric loads (moment loads), the supply pressure and the speed of rotation. In this paper, by the use of an apparatus featuring circular hydrostatic thrust bearings acting on concentric loads, we measure the frictional force and leakage flow rate under a lubrication range from mixed to fluid film. The surface roughness, the supply pressure, the loads, the speed of rotation and the restrictors are selected as main experimental parameters. We evaluate the coefficient of friction, the leakage flow rate and power losses for the bearing-modulus and the ratios of hydrostatic balance. Furthermore, these experimental results are compared with the theoretical ones. The conclusions are as follows : 1) the minimum power losses are given by the ratio of hydrostatic balance being close to unity independent of the surface roughness, the loads, and the speed of rotation; 2) the coefficient of friction of hydrostatic bearings can be clarified generally versus a bearing-modulus by use of the load carrying capacity due to asperities; 3) a larger surface roughness, causes a larger leakage flow rate in mixed lubrication; 4) the larger the supply pressure, the larger the power losses in fluid film and under mixed lubrication; 5) the larger the speed of rotation, the larger are the proportional power losses under mixed lubrication; 6) the size of restrictors seldom have any effects under mixed lubrication conditions.