A compiler, which corresponds to a recent processor having a multithread function, that enables execution of efficient instruction scheduling and allows a programmer to control the instruction scheduling includes: an instruction scheduling directive receiving unit which receives, from a programmer, a directive for specifying an instruction scheduling method; and an instruction scheduling unit which executes, conforming to one of instruction scheduling methods, instruction scheduling of rearranging intermediate codes corresponding to the source program. The instruction scheduling unit selects one of instruction scheduling methods according to the directive received by the instruction scheduling directive receiving unit, and executes instruction scheduling conforming to the selected instruction scheduling method.