The present invention relates to a compound having a tricyclic amine substituent which may have various substituents, the compound being represented by formula (I), a salt or hydrate thereof, and a hydrate of the salt and a drug containing them as an active ingredient. They exhibit excellent antimicrobial activity against Gram negative bacteria and Gram positive bacteria with a satisfactory fate and safety and are useful in the treatment of infectious diseases. wherein Q preferably represents the following partial structure which may have various substituents: