A hyaluronic acid derivative in which an anti-inflammatory drug is bound tohyaluronic acid through a covalent bond via a space having a biodegradableregion, and aproduction process thereof. In one preferred aspect, the present inventionprovides aderivative which is represented by the following formula (3):H2N-R1-(O-R2)n (3)wherein R2 represents a hydrogen atom or a non-steroidal anti-inflammatorydrugresidue, and at least one R2 is a non-steroidal anti-inflammatory drugresidue； H2N-R1-(O-)n represents a spacer residue in a spacer compound represented by H2N-R1-(OH)nhaving n numbers of hydroxyl group； wherein a hydroxyl group in the spacercompoundforms an ester bond with a carboxyl group in the non-steroidal anti-inflammatory drugresidue when R2 is a non-steroidal anti-inflammatory drug residue； R1represents a linearor branched hydrocarbon group having from 2 to 12 carbon atoms which may haveasubstituent； and n is an integer of from 1 to 3.
