The substrate with a heat generating element 15 comprises a protection layer 16-1 made of silicon oxide, silicon nitride or silicon carbide, an outermost protection layer 16-2 made of a metal such as platinum or metal oxide thereof, preferably made of tantalum or oxide of tantalum, electrodes 17-1 and 17-2 made of aluminum, gold or aluminum???copper alloy, a heat generating resistor layer 18 made