PURPOSE: To reduce load to a system by utilizing a business job equally for any user and to immediately judge whether the business job can be executed or not at an execution request source.

CONSTITUTION: A multiplex degree registering means 1 prepares a multiplex degree managing file 2 and performs the initialization and change of a multiplex degree managing table 4. When the execution of the business job is requested, multiplex degree inspection means 5a and 5b inspect whether the execution request of the business job can be accepted or not by retrieving the multiplex degree managing table 4, and when the execution request can not be accepted, the execution request is ignored, and error notice is returned to a terminal at the execution request source. When the start request of the business job is issued from business start requesting means 6a and 6b, a multiplex degree managing means 3 starts the business job and updates the multiplex degree state of the business job in the multiplex degree managing table 4, and when the end notice of the business job is received from business end notice means 8a and 8b, the multiplex degree state of the business job in the multiplex degree managing table 4 is updated.