The compound of the present invention is a novel compound which has a specific heterocycle skeleton, particularly a pyrazolonaphthyridine or pyrazoloquinoline skeleton having an organic group (e.g., a carbocycle and a heterocycle) bonding through an alkylene group at 3-position and a carbocycle bonding at 5-position and has a phosphodiesterase IV inhibitory activity. At least one of the ring (the carbocycle or the heterocycle) bonding at 3-position of the pyrazolonaphthyridine skeleton and the carbocycle bonding at 5-position may have a halogenated alkyl group and/or a halogenated alkoxy group as a substituent. Such a compound or a salt thereof is useful as a phosphodiesterase IV inhibitor and the like. According to the present invention, a novel compound having a high phosphodiesterase IV inhibitory effect can be provided.
