Electrical resistivity measurements of hematite (α-Fe2O3) were performed under shock compression in the range of 240--760kbar. The specimens used were coarsely polycrystalline natural material from Brazil. The electrical resistivity decreases gradually with increasing shock pressure to 440 kbar and decreases discontinuously to less than 1 &OHgr; cm from several tens of ohm centimeters at pressures of 440--520 kbar. The phase transformation pressure, implied in Hugoniot equation-of-state experiments, is made clear. The transition behavior into the low-resistivity state depends on the crystallographic axis of shock propagation.