The present invention relates to novel compounds having a histone deacetylase 6 (HDAC6) inhibitory activity, stereoisomers thereof or pharmaceutically acceptable salts thereof, a medicinal use thereof, and a method for preparing the same. The novel compounds according to the present invention, stereoisomers thereof or pharmaceutically acceptable salts thereof have the histone deacetylase 6 (HDAC6) inhibitory activity, and are effective in preventing or treating HDAC6-related diseases, comprising infectious diseases; neoplasm; endocrinopathy; nutritional and metabolic diseases; mental and behavioral disorders; neurological diseases; eye and ocular adnexal diseases; circulatory diseases; respiratory diseases; digestive diseases; skin and subcutaneous tissue diseases; musculoskeletal system and connective tissue diseases; and teratosis or deformities, or chromosomal aberration.