A quinolone compound represented by the General Formula (1): ** Formula ** or a salt thereof, wherein R 1 represents: (3) halogen-substituted C 1 -C 6 alkyl, (4) C 2 -C 6 alkenyl , (5) C1-C6 alkanoyl, (6) halogen substituted C1-C6 alkanoyl, (7) C1-C6 hydroxy-alkyl, (8) C1-C6 phenyl-alkoxy-C1-C6 alkyl, ( 9) C1-C6 hydroxy-alkanoyl, (10) C1-C6-phenyl-C1-C6-alkoxy, (11) C1-C6-thio-C1-C6-alkyl, (12) amino-C1-alkyl C6-thio-C1-C6 alkyl optionally having one or two C1-C6 alkyl groups, (13) hydroxy-C1-C6 alkyl-thio-C1-C6 alkyl, (14) C1-C6-thio carboxy alkyl -C1-C6 alkyl, (15) C1-C6-alkoxy-C1-C6-alkylthio-C1-C6 alkyl, (16) C1-C6 amino-alkyl-C1-C6-thiocarbonyl-alkyl optionally having one or two C1-C6 alkyl groups, (17) hydroxy-C1-C6 alkyl-sulfonyl-C1-C6 alkyl, (18) carboxy-C1-C6 alkyl-sulfonyl-C1-C6 alkyl, (19) C1- alkoxy C6-carbonyl-C1-C6 alkyl-sulfonyl-alkyl C1-C6, (20) C1-C6 alkanoyl-C1-C6 alkyl-sulfonyl-C1-C6 alkyl, (21) piperazinyl-C1-C6 alkyl-sulfonyl-C1-C6 alkyl optionally having a C1-alkyl group -C6 in the piperazine ring, (22) piperazinylcarbonyl-C1-C6 alkyl-sulfonyl-C1-C6 alkyl optionally having a C1-C6 alkyl group in the piperazine ring, (23) C1-C6-alkanoyl alkyl C1-C6, (24) C1-C6 carboxy-alkyl, (25) C1-C6-alkoxy-C1-C6 alkyl, (26) piperazinyl-C1-C6-alkoxy-C1-C6 alkyl which optionally has a C1-C6 alkyl group in the piperazine ring, (27) morpholinyl-C1-C6 alkyl, (28) oxazepanyl-C1-C6 alkyl, (29) amino-C1-C6 alkyl which optionally has one or two C1-C6 alkyl groups, (30) piperazil-C1-C6 alkyl optionally having, in the piperazine ring, a substituent selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy of C1-C6, and pyridyl, (31) piperidyl-C1-C6 alkyl having optionally te a morpholinyl group, (32) azetidyl-C1-C6 alkyl which optionally has a hydroxy group in the azetidine ring, (33) isoindolinyl-C1-C6 alkyl which optionally has one or two oxo groups, (34) amino -C1-C6-alkanoyl-C1-C6 alkyl having optionally one or two substituents selected from the group consisti
