An image processing apparatus includes a hardware processor that: calculates a representative signal value in a region where no signal value variations attributable to dynamic states of an object are present, in each of a plurality of frame images acquired by consecutively applying radiation onto the object a plurality of times, and extracts high-frequency components of changes over time in the calculated representative signal values； and corrects signal value variations attributable to a fact that an irradiation amount varies each time the radiation is applied, by subtracting the extracted high-frequency components from the plurality of frame images, respectively, or dividing the plurality of frame images by the extracted high-frequency components, respectively.
