A novel agent which is effective in the prevention or treatment of a chronic respiratory disease such as COPD, interstitial pneumonia and asthma is provided. The therapeutic agent for a chronic respiratory disease comprises, as an active ingredient, a hydroquinone derivative represented by general formula (1) wherein R1 represents an alkyl group having 4 to 8 carbon atoms, and R2 represents a hydrogen atom, an alkylcarbonyl group having 2 to 6 carbon atoms or an alkoxycarbonyl group having 2 to 6 carbon atoms.