A apparatus and a method for virtualizing memory

PURPOSE: An apparatus and a method for virtualizing a memory are provided to improve the performance of a virtualizing system by rapidly mapping memories in order to change page tables of a guest operating system in the virtualizing system. CONSTITUTION: Shadow page tables(62) are generated respectively for guest operating systems. A guest page table is provided from one of the guest operating systems as the reference of a physical memory page. A processor processes mapping information which maps one of the shadow page tables and the guest page table. The mapping information is machine address information in which the guest operating system is loaded and is the virtual address information of the guest page table.