PURPOSE: To shorten an unnecessary lock waiting time or a necessary time until resources are secured by providing a means to execute lock reservation in advance.

CONSTITUTION: An exclusive control means 1, lock holding means 2 to hold the lock of a task which outputs a reservation request, unheld reservation chang ing means 3, lock permitting means 4 and holding reservation changing means 5 are provided. Then, a reservation change processing part 6 to execute the change of the reservation request and an exclusive control table 7 are provided. The exclusive control table 7 defines a resource name, which is a name for uniquely identify the exclusive control objective resources in a system, as a key and an entry corresponding to the respective resources is composed of a resource name part, lock mode part, list of a task under locking, lock waiting and reserving task cue, holding task list and request inserting position pointer. Thus, when the processing is executed by simultaneously using the plural resources, since the lock reservation can be executed in advance, the lock wait ing time not needed for the other task and the time up to the securing of all the request resources are shortened.