Abstract: Quinolinecarboxylic acid derivatives which are represented by the general formula (I) ##STR1## wherein R.sub.1 is a C.sub.1 to C.sub.6 alkyl group which may be substituted, a C.sub.2 to C.sub.6 alkenyl group which may be substituted, a C.sub.3 to C.sub.7 cycloalkyl group which my be substituted or an aryl group which may be substituted,R.sub.2 is hydrogen atom; a halogen atom; hydroxyl group which may be protected, amino group or a C.sub.1 to C.sub.6 alkylamino group each of which may be protected; a C.sub.1 to C.sub.6 dialkylamino group or a C.sub.1 to C.sub.6 alkyl group,R.sub.3 is hydrogen atom or a C.sub.1 to C.sub.6 alkyl group,A is nitrogen atom or ##STR2## wherein A' is hydrogen atom. a halogen atom, a C.sub.1 to C.sub.6 alkyl group, a C.sub.1 to C.sub.6 alkoxyl group which may be substituted, cyano group, or nitro group, and A' may form a ring with R.sub.1 ; the ring may include oxygen atom, nitrogen atom, or sulfur atom as a constituent atom; the ring may be substituted with a C.sub.1 to C.sub.