A processing device includes an instruction extractor that extracts target instructions intended for a loop process that is repeatedly performed, from instructions decoded by an instruction decoder, and a loop buffer including entries where each of the target instructions extracted by an instruction extractor are stored. An instruction processor stores a target instruction into one of the entries of the loop buffer, and combines target instructions into one target instruction in a case where resources of an instruction execution circuit used by the target instructions do not overlap, to store the one instruction in one of the entries of the loop buffer, and a selector selects the instruction output from the instruction decoder or the target instruction output from the loop buffer, and outputs the selected instruction to the instruction execution circuit.