To provide an application switching control system for preventing memory leakage generated when a secured memory is often left as it is without being released though a program dynamically secures a certain memory when a storage area is required and the secured memory is released when the memory is unnecessary in order to effectively utilize the memories of a computer system.

Program start controlling software 1 sets up index information 101, 102 and software generation identification information 111, 112 in a software management part 10 and collectively manages the start control of programs 30, 31. A new program 31 to 30 is periodically substituted for an old program 30 or 31 on the basis of information from time monitoring software 2 and memory leakage which may be included in the old program is automatically restored without stopping service itself provided from an application 3.