In a high-speed address translation system provided in a computer system including a logical address space storing logical addresses, a physical address space for storing physical addresses and a microprocessor unit connected to both address spaces, and the microprocessor unit including a memory management unit (MMU), the system according to the present invention includes; a TLB provided in the MMU for translating the logical address to the physical address; and a unit for adjusting a size of each section formed of a file to a predetermined page size in an offline process in accordance with memory allocation designed in the offline process.