According to the conventional loop parallelization method, when a loop in which a value of a loop-carried dependency variable can be calculated in all of the iterations without sequentially executing the loop from the start, it is determined that DOALL parallelization is not applicable due to the loop-carried dependency variable. Accordingly, the loop is sequentially executed or parallelized by using DOACROSS parallelization that executes a loop including a loop-carried dependency variable. That is, there is a problem that an expression including a loop-carried dependency cannot be parallelized and efficiently processed with use of a multi-processor. By generating initial value calculating codes, the loop-carried dependency in a source code prior to parallelization can be solved, and by dividing a loop included in the source code into subloops that can be executed in parallel, the multi-processor can efficiently process the source code.