A demand paging apparatus and a method for an embedded system are provided. The demand paging apparatus includes a nonvolatile storage device, a physical memory, a demand paging window, and a demand paging manager. The nonvolatile storage device stores code and data which are handled by demand paging. The physical memory processes information about a requested page that is read from the nonvolatile storage device. The demand paging window generates a fault for the page and, thus, causes demand paging to occur. The demand paging window is part of an address space to which an application program stored in the nonvolatile storage device refers. The demand paging manager processes the page fault generated in the demand paging window.