A tricyclic compound represented by the formula <wherein R 1A represents lower alkyl optionally having substituent(s), cycloalkyl optionally having substituent(s), lower alkoxy optionally having substituent(s) or lower alkylsulfanyl optionally having substituent(s), R 2A and R 3A are the same or different and each represents a hydrogen atom, lower alkyl optionally having substituent(s), lower alkenyl optionally having substituent(s), lower alkanoyl optionally having substituent(s), lower alkoxycarbonyl optionally having substituent(s), lower alkylcarbamoyl optionally having substituent(s), di-lower alkylcarbamoyl optionally having substituent(s) or aliphatic heterocycle-carbonyl optionally having substituent(s), or a group in the formula is selected from the group consisting of the following formulas to [wherein R 1A is as defined above, R 6A and R 7A are the same or different and each represents a hydrogen atom, halogen, nitro, cyano, formyl, oxo, hydroxy, lower alkoxy optionally having substituent(s), lower alkanoyloxy optionally having substituent(s), lower alkyl optionally having substituent(s), lower alkenyl optionally having substituent(s), lower alkanoyl optionally having substituent(s), lower alkoxycarbonyl optionally having substituent(s), -NR 9A R 10A (wherein R 9A and R 10A are the same or different and each represents a hydrogen atom, lower alkyl optionally having substituent(s), lower alkanoyl optionally having substituent(s), lower alkoxycarbonyl optionally having substituent(s) or aralkyl optionally having substituent (s), or R 9A and R 10A form, together with the adjacent nitrogen atom thereto, a nitrogen-containing heterocyclic group optionally having substituent(s)), -CONR 11A R 12A (wherein R 11A and R 12A are the same or different and each represents a hydrogen atom, lower alkyl optionally having substituent(s), lower alkanoyl optionally having substituent(s), lower alkoxycarbonyl optionally having substituent(s) or aralkyl optionally having substituent(s), or R 11A and R 12A form, together with the adjacent nitrogen atom thereto, a nitrogen-containing heterocyclic group optionally having substituent(s)), aryl optionally having substituent(s), aralkyl optionally having substituent(s), an aromatic heterocyclic group optionally having substituent(s) or an aliphatic heterocyclic group optionally having substituent(s), and R 8A represents a hydrogen atom or lower alkyl optionally having substituent(s)], R 4A and R 5A are the same or different and each represents a hydrogen atom, halogen, hydroxy, lower alkoxy or lower alkyl, Q 1A -Q 2A -Q 3A represents CH=CH-CH=CH, Y A represents CH 2 CH 2 or CH 2 O, Z 1A -Z 2A represents C=CR 13A (wherein R 13A represents a hydrogen atom or lower alkyl optionally having substituent(s)), CH-CR 14A R 15A (wherein R 19A and R 15A are the same or different and each represents a hydrogen atom or lower alkyl optionally having substituent (s)), or N-CR 16A R 17A (wherein R 16A and R 17A are the same or different and each represents a hydrogen atom or lower alkyl optionally having substituent(s)), and (i) when Z 1A -Z 2A is C=CR 13AA (wherein R 13AA represents lower alkyl optionally having substituent(s)), CH-CR 14A R 15AA (wherein R 14A is as defined above, and R 15AA represents lower alkyl optionally having substituent(s)), or N-CR 16AA R 17A (wherein R 16AA is lower alkyl optionally having substituent(s) and R 17A is as defined above), A A represents a group selected from the group consisting of the following formulas and (ii) when Z 1A -Z 2A is C=CR 13AB (wherein R 13AB represents a hydrogen atom), CH-CR 14AB R 15AB (wherein both of R 14AB and R 15AB represent,a hydrogen atom), or N-C-R 16AB R 17AB (wherein both of R 16AB and R 17AB represent a hydrogen atom), A A represents the group of formula or a pharmaceutically acceptable salt thereof; wherein lower alkyl and the lower alkyl moiety of lower alkoxy, lower alkylsulfanyl, lower alkanoyloxy, lower alkanoyl, lower alkoxycarbonyl, lower alkylcarbamoyl and di-lower alkylcarbamoyl means a straight chain or branched alkyl having 1 to 10 carbon atoms, and two lower alkyl moieties of di-lower alkylcarbamoyl may be the same or different; and wherein the term lower alkenyl means a straight chain or branched alkenyl having 2 to 10 carbon atoms.