ABNORMALITY DETERMINATION DEVICE, ABNORMALITY DETERMINATION METHOD, AND ABNORMALITY DETERMINATION SYSTEM

An abnormality determination device includes: an acquisition unit configured to acquire a resistance value of an electric heating element calculated from a voltage across the electric heating element of a heater and a current flowing through the electric heating element and configured to acquire a temperature value of the heater; a first determination unit configured to perform abnormality determination based on the acquired resistance value; a second determination unit configured to determine whether or not the acquired temperature value is in a temperature settling state where the acquired temperature value is within a width with respect to a first target value; and a third determination unit configured to determine whether or not the acquired resistance value is in a resistance settling state where the acquired resistance value is within a width with respect to a second target value. The first determination unit performs the abnormality determination when the second determination unit determines that the temperature settling state is established over a first period and the third determination unit determines that the resistance settling state is established over a second period.