The hydro-mechanical behavior of the Earth's crust heavily relies on the fractional volume and geometrical structure of effective pore spaces. In this paper we made an attempt to understand the characteristics of pore using electrical impedance. We measured the electric impedance of the core samples (diameter of 38-50mm and length of 70-100mm) of 3 types of granites (Hwangdeung, Pocheon, and Yangsan grs.) and 2 types of sandstones (Boryung and Berea ss.) with different porosity and pore structure after the saturation in turn with saline water with different salinity. Our results show that resistance decreases but capacitance increases with increasing the salinity of pore fluid. Under the condition of the same salinity, the resistivity and the formation factor are reduced by increasing porosity of rocks, the capacitance is raised by the porosity. Berea sandstone exhibits an anisotropy of the resistance, tortuosity and cementation factor so that they are the highest across the bedding planes. This implies that the connectivity of pores is the weakest across the bedding. Our conclusion is that the electrical characteristics of tested samples are related not only their porosity but also its geometry.