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. The compound or a salt thereof of the present invention has a glucocorticoid receptor agonist activity, and is useful as a medicine, in particular as a prophylactic or therapeutic agent for the glucocorticoid receptor related disease.