1. A scheduling method for scheduling tasks providing a system designed on an object-oriented basis by using a computer, comprising: a first step of extracting classes forming said system from design information thereof, generating tasks corresponding to the extracted classes, and storing information on the generated tasks into a given storage device; a second step of extracting dependency between the classes from the design information of said system, setting the dependency between the corresponding tasks on the basis of the dependency, and storing information on the set dependency between the tasks into the given storage device; and a third step of scheduling the tasks on the basis of the information on the tasks stored in said given storage device and the information on the dependency between the tasks.