The present invention relates to a novel [4-(1, 3, 3-trimethyl-2- oxo-3, 4-dihydro-1H-quinoxalin-7-yl)phenoxy]ethyloxy compound or a salt thereof. A compound of the present invention or a salt thereof has glucocorticoid receptor agonist activity, and is useful as a pharmaceutical product, especially as a prophylactic and/or therapeutic agent for diseases associated with a glucocorticoid receptor.