The present invention relates to a morphinan derivative represented by the following general formula (I), wherein R 1 represents hydrogen, C 1-6 alkyl, C 6-10 aryl, etc., R 2 and R 3 , which are the same or different, represent hydrogen, hydroxy, ect., R 4 and R 5 represent hydrogen, C 1-6 alkyl, etc., R 6 represents hydrogen, hydroxy, C 1 - 6 alkyl, etc., X represents O or CH 2 , Y represents C=O, C(=O)O, etc., and m and n, which are the same or different, represent an integer of 0 to 2 (m and n are not 0 at the same time), a tautomer or stereoisomer of the compound, or a pharmaceutically acceptable salt thereof, or a solvate thereof, as well as an analgesic, antianxiety drug, etc. containing the same as an active ingredient.