An image data processing apparatus includes: a plurality of operational processing circuits each of which is configured to have a variable circuit configuration and to execute operational processing on image data; and a control section that controls each of the operational processing circuits such that each of the operational processing circuits executes one of a plurality of types of operational processing performed on image data in a predetermined order. The control section controls each of the operational processing circuits so that when image data to be newly given to one of the operational processing circuits is interrupted, said one of the operational processing circuits and another one of the operational processing circuits execute operational processing by taking partial charge of the operational processing.