An image data processing apparatus includes a configuration selecting unit, a loading unit, and a controller. The configuration selecting unit determines types of image characteristics of individual processing units in image data and selects plural pieces of circuit configuration data for individual processing units. The loading unit predicts a predetermined number of pieces of circuit configuration data in descending order of the likelihood of being selected for the processing unit currently being processed, and loads, before selection of the circuit configuration data for the processing unit, the predetermined number of pieces of configuration data into a circuit configuration memory for a reconfigurable circuit. If the selected circuit configuration data has already been loaded, the controller causes the circuit configuration to be reconfigured. If the selected circuit configuration data has not been loaded, the controller causes the selected circuit configuration data to be loaded and the circuit configuration to be reconfigured.