A high-sped block is formed by generating and connecting a new basic block (contains an intermediate code obtained by performing variable replacing processing to a path replacement target variable of the intermediate code on a hot path of an original partial program and contains a branching intermediate code where a branching instruction on the hot path is converted so as to execute the hot path), and a basic block with an intermediate code for restoring value of path guarantee variable among the path replacement target variables to a value of an original variable. When an execution result of a conditional branching intermediate code is true, the speeding up of the original program is achieved through executing the basic block, and performing dependency analysis and dependency generation between the intermediate codes in the high-speed block and scheduling of the instructions.