Disclosed is a device for maintaining consistency between a host system cache and a main memory in a general-purpose computing system equipped with a hardware accelerator for processing main memory data. The device for maintaining data consistency between a hardware accelerator and a host system, which is at least temporarily implemented by a computer, includes a determination unit responsible for determining whether an address which the hardware accelerator should access is present in a cache, and a processing unit responsible for selectively performing write-back on data corresponding to the address when the address is present in the cache based on the determined result.