A heating device includes a rotating member that rotates, and plural unit circuits that are aligned in a width direction of the rotating member. The plural unit circuits each includes a heating body that heats the rotating member, a resistive element that is connected in series to the heating body and has a positive temperature coefficient, and a parallel circuit that is connected in parallel to the resistive element. The unit circuits are each configured such that, if a resistance value of the resistive element is increased with a rise of temperature of the resistive element, a current flows through the parallel circuit.