Ba2Bi4Ti5O18 single crystals were grown, and their dielectric permittivity, conductivity, and ferroelectricity were investigated along the a-(or b-)axis and the c-axis separately. The dielectric permittivity at 1 MHz along the a-(or b-)axis was 2000 at the Curie temperature (360°C); this value was 8 times greater than that along the c-axis. The dc conductivity was greater along the a-(or b-)axis than that along the c-axis, by one order of magnitude. In regard to the ferroelectricity, the saturated remanent polarization was 120 mC/m2 and the saturated coercive field was 3 MV/m along the a-(or b-)axis; values of 8.5 mC/m2 and 0.81 MV/m, respectively, were observed along the c-axis. The Ba2Bi4Ti5O18 single crystals had large electrical anisotropies, which were due to the layered structure.