1. A parallel processing device comprising: a first processor executing, on input data, a first program that prescribes unit processing to be executed by using data included in data sets as the input data to output a first result; a second processor executing a second program that prescribes the unit processing on the input data to output a second result; a selection unit selecting a first subset and a second subset from the data set based on a predetermined index indicating performance or function of the first processor and the second processor; a first processor control unit inputting first data included in the first subset to the first processor; and a second processor control unit inputting second data included in the second subset to the second processor, the first program and the second program being executed in parallel by the first processor and the second processor.