Provided is a parallel processing device whereby a plurality of single processes is efficiently and simply parallel processed by a plurality of processors. The parallel processing device includes: a first processor which executes, upon data which is included in data sets, a first program which defines a single process which is executed with the data as an input thereof, and outputs a first result; and includes a second processor which executes, upon the inputted data, a second program which defines a unit process and outputs a second result. A selection unit selects, based on a prescribed index which denotes either performance or function of the first processor and the second processor, a first partial set and a second partial set from the data set. A first processor control unit inputs into the first processor first data which is included in the first partial set. A second processor control unit inputs into the second processor second data which is included in the second partial set. The first and second programs are executed in parallel by the first and second processors.