TWI823348B

An abnormality determination device includes an acquisition unit configured to acquire a resistance value and a power value of an electric heating element of a heater calculated from a voltage across the electric heating element and a current flowing through the electric heating element, a first determination unit configured to perform an abnormality determination that is a determination of whether the heater is abnormal based on the acquired resistance value, and a second determination unit configured to determine whether the acquired power value is in a power settling state where the acquired power value is within a width with respect to a first target value. The first determination unit performs the abnormality determination based on the acquired resistance value when the second determination unit determines that the power settling state is established over a first period.