A planar resistance heating element with positive temperature coefficient characteristics includes a resistive body layer formed of a crystalline resin containing electrically conductive particles and disposed between at least a pair of electrodes on an insulating substrate. A phenolic resin layer or a denatured phenolic resin layer with an elastomer resin added is disposed on the resistive body layer in covering relation to the entire surface thereof. An insulating protective film of resin may be disposed on the covering layer with an adhesive layer interposed therebetween, and an adhesive layer may be disposed on an outer surface of the insulating protective film for attachment to an object to be heated.
