Ni-SDC cermet SOFC anodes with different microstructures were prepared and the overpotential and the ohmic loss were measured. Anodes with coarse particles and small pores showed intermediate performance and little dependence on flow rate, whereas that with large pores showed a large dependence on flow rate and high performance at high flow rate. Anodes with fine particles showed lowest overpotential at low current density. Ohmic loss was large for the thick electrode with small pores, and for that with large pores, when flow rate was low. It is considered that different particle size and pore size lead to the difference in effective reaction zone, thus showing different dependence to the flow rate.