The present invention relates to a morphinan derivative as represented by general formula (I) a tautomer or stereoisomer of said compound a pharmaceutically acceptable salt thereof a solvate of the morphinan derivative or of a tautomer, stereoisomer, or pharmaceutically acceptable salt thereof and an analgesic, an anxiolytic agent, or the like that includes any of the above as an active ingredient. In general formula (I), R1 represents hydrogen, a C16 alkyl, a C610 aryl, or the like R2 and R3 are the same or different and represent hydrogen, a hydroxyl, or the like R4 and R5 represent hydrogen, a C16 alkyl, or the like R6 represents hydrogen, a hydroxyl, a C16 alkyl, or the like X represents O or CH2 Y represents C=O, C(=O)O, or the like and m and n are the same or different and represent an integer from 0 to 2 (provided that both m and n are not simultaneously 0).
