To collect frequencies with which processes of a program are executed at high speed. A compiler apparatus for optimizing a program based on frequencies with which each process is executed has a loop process detection portion for detecting a repeatedly executed loop process of the program, a loop process frequency collection portion for collecting loop process frequencies with which the loop process is executed in the program, an in-loop process frequency collection portion for collecting in-loop process frequencies with which, as against times of execution of loop process, each of a plurality of in-loop processes included in the loop process is executed, an in-loop execution information generating portion for generating in-loop execution information indicating the frequencies with which each of the plurality of in-loop processes is executed in the case where the program is executed, and an optimization portion for optimizing the program based on the in-loop execution information.