The exemplary embodiments of the invention relates to fault tolerance of a cache memory which recovers an error occurred in the cache memory or reports an error. A cache memory may include a first layer cache configured to store data requested from a processor, together with a tag related to the data and parity check bits for detecting data error and tag error; a second layer cache configured to store data requested from the first layer cache, together with parity check bits and an error correction code(ECC) bit for detecting data error and tag error; and a fault tolerance unit configured to generate an error signal indicating whether the data error or tag error occurred in at least one of the first layer cache and the second layer cache is recoverable.