1. A program converting method executed by a processor for analyzing a parallel language program and converting the parallel language program into a sequential language program that is subject to a distributed processing by a plurality of processors, the method comprising: generating a setting code for setting a value in a distribution parameter for each of the plurality of processors; generating a localizing code before a loop that is aligned to a template, the localizing code being for localizing indexes in the loop and for converting a global index to a local index, and referencing loop variable as a subscript; and localizing an array index for an array, and performing the converting unless the array is aligned to a template for use in array distribution to the plurality of processors, thereby excluding the subscript from a loop index calculation.