This paper is concerned with the experimental investigation of electrorheological effect (ER effect) on apparent viscosity and yield stress obtained from hydrodynamic characteristics of electrorheological fluid (ERF) in various flow fields. Our conducting flow fields are made by using rectangular duct, concentric cylindrical pipe, rotating disk and rotating concentric cylinder. The measured parameters of the former two cases are pressure difference at a given volumetric flow rate, and the latters are torque at a given angular velocity. Our using ERF is suspension type. We arrange these data to obtain increment of apparent viscosity and yield stress with and without a supplying D.C. electric field by using integral method of rheology. It is clarified that qualitative values of increment of apparent viscosity and yield stress are different at each flow field. In addition, the quantitative ER effects of shear rate and electric field strength on the increment of apparent viscosity and yield stress are clarified.