A code conversion apparatus includes a memory and a processor coupled to the memory. The memory is configured to store therein a first code including a first data definition of a plurality of arrays, a first operation for the plurality of arrays, and a second data definition of an array indicating a result of the first operation. The processor is configured to convert the first data definition and the second data definition included in the first code into a data definition of an array of structures. The processor is configured to convert the first operation included in the first code into a second operation for the array of structures. The processor is configured to generate a second code including a predetermined instruction to perform the second operation on different pieces of data of the plurality of arrays in parallel with one another.