PURPOSE: To easily obtain copper oxide-based electrically conductive ceramics represented by a prescribed formula and having heat and corrosion resistances by heating a mixture of the nitrates of In, Sc, Y, etc., with copper nitrate at a prescribed temp.

CONSTITUTION: The nitrates of one or more kinds of elements (M) selected among In, Sc, Y, Tl and Ga are mixed with copper nitrate and this mixture is heated at 200-600°C to obtain copper oxide-based electrically conductive ceramics represented by a formula (MxCuy)7Oz(NO3) (where x+y=1, x/y=0-10 and z is 6-8).