The present invention relates to a hydroxamic acid derivative of the formula (I) wherein each symbol is as defined in the specification, a pharmacologically acceptable salt thereof, a pharmaceutical composition containing the derivative or a salt thereof, and to pharmaceutical use thereof. The hydroxamic acid derivative and a pharmacologically acceptable salt thereof of the present invention have an inhibitory activity of TNF &agr; production, and are useful for, for example, the prophylaxis and treatment of the diseases such as autoimmune diseases and inflammatory diseases (e.g., sepsis, MOF, rheumatoid arthritis, Crohn's disease, cachexia, myasthenia gravis, systemic lupus erythematosus, asthma, I type diabetes, psoriasis and the like), and the like.