1. A job scheduling method for scheduling of job allocation to various resources comprising the steps of: inputting data associated with jobs and resources; allocating a workload of each job to each time unit along a time axis in units of job; allocating said workload to said each time unit in units of resource type; calculating an initial workload for all resources at said each time unit, in accordance with said workload allocated in units of resource type; performing a first workload balancing for a time unit whose initial workload for all resources exceeds a resource capacity, so as to make the workload at said time unit within said resource capacity; after said first workload balancing, performing a second workload balancing so as to make the workload allocated in units of resource type within its resource capacity; and outputting, as a job schedule, each workload at said each time unit obtained by said second workload balancing.