In programming in high-level language, a method of generating a program supporting external specifications for generating secure codes having high tamper-resistance and automatically generating an executable program having tamper-resistance with regard to a portion designated by a user is provided. A syntax analysis step, an intermediate representation generation step, a register allocation step, an optimization processing step, an assembly language generation step, a machine language generation step and a machine language program linkage step are executed. And between finish of reading of the source program and generating the executable program, a tamper-resistant code insertion step of automatically generating a code having tamper-resistance coping with unjust analysis of an operation content of the executable program is executed to the source program, the intermediate representation, the assembly language program or the machine language program based on an instruction of a user.