The CPU includes a byte code interpretation unit that sequentially reads intermediate code instructions along an execution route, determining whether or not there is a compilation result of the read intermediate code instruction in the compilation result storage unit, interpreting the intermediate code instruction when there is no compilation result, and designating the compilation result if there is a compilation result; and a program execution unit that, if received the interpretation result of the intermediate code instruction from the byte code interpretation unit, executes the intermediate code instruction and, if received the designation of the compilation result, executes the program by executing designated native code. The CPU includes a compilation execution unit that compiles the intermediate code instruction interpreted by the byte code interpretation unit to generate the native code and stores them in the compilation result storage unit.