The present technology relates to a storage device that allows access to the storage device without accessing a main memory of a host by allocating a portion of a mapping area of a buffer memory to a cache area. The storage device includes a memory device including a plurality of memory cells, a memory controller configured to control an operation performed on the memory device, and a buffer memory including a cache area and a mapping area in which mapping data indicating a mapping relationship between a logical block address and a physical block address corresponding to the operation is stored. The buffer memory allocates a portion of the mapping area to the cache area according to an allocation request received from a host, and stores data except for the mapping data in the cache area.