A method for producing L-arginine or L-lysine, comprising the steps of (a) culturing a coryneform bacterium in a medium to produce and (b) accumulate L-arginine or L-lysine in the medium and (c) collecting the L-arginine or L-lysine from the medium, wherein said coryneform bacterium has an L-arginine- or L-lysine-producing ability and is modified so that glutamine synthetase activity is enhanced by (i) modifying an adenylylation site of glutamine synthetase so that activity regulation of glutamine synthetase by adenylylation is reduced compared with that of a wild strain or unmodified strain of a coryneform bacterium, or eliminated, (ii) disrupting a gene encoding the glutamine synthetase adenylyltransferase on a chromosome of said bacterium, (iii) disrupting a gene encoding PII protein on a chromosome, wherein the gene encoding PII protein is selected from the group consisting of: a) a DNA having the nucleotide sequence of SEQ ID NO: 23, b) a DNA encoding a protein having PII activity and being hybridizable with the nucleotide sequence of SEQ ID NO:23 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, (iv) disrupting the amtR gene on a chromosome of said bacterium, wherein the amtR gene is selected from the group consisting of: a) a DNA having the nucleotide sequence of SEQ ID NO: 21, b) a DNA encoding a protein having AmtR activity and being hybridizable with the nucleotide sequence of SEQ ID NO:21 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, or (v) enhancing expression of a gene encoding glutamine synthetase by replacing an expression regulatory sequence with a stronger one, and wherein said coryneform bacterium is modified so that the activity of the arginine repressor is reduced or eliminated as compared with a wild type strain or unmodified strain, wherein the arginine repressor is selected from the group consisting of: a) a. protein encoded by a DNA having the nucleotide sequence of SEQ ID NO: 15, b) a protein having arginine repressor activity and being encoded by a DNA that is hybridizable with the nucleotide sequence of SEQ ID NO:15 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C. (a) culturing a coryneform bacterium in a medium to produce and (b) accumulate L-arginine or L-lysine in the medium and (c) collecting the L-arginine or L-lysine from the medium, (i) modifying an adenylylation site of glutamine synthetase so that activity regulation of glutamine synthetase by adenylylation is reduced compared with that of a wild strain or unmodified strain of a coryneform bacterium, or eliminated, (ii) disrupting a gene encoding the glutamine synthetase adenylyltransferase on a chromosome of said bacterium, (iii) disrupting a gene encoding PII protein on a chromosome, wherein the gene encoding PII protein is selected from the group consisting of: a) a DNA having the nucleotide sequence of SEQ ID NO: 23, b) a DNA encoding a protein having PII activity and being hybridizable with the nucleotide sequence of SEQ ID NO:23 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, a) a DNA having the nucleotide sequence of SEQ ID NO: 23, b) a DNA encoding a protein having PII activity and being hybridizable with the nucleotide sequence of SEQ ID NO:23 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, (iv) disrupting the amtR gene on a chromosome of said bacterium, wherein the amtR gene is selected from the group consisting of: a) a DNA having the nucleotide sequence of SEQ ID NO: 21, b) a DNA encoding a protein having AmtR activity and being hybridizable with the nucleotide sequence of SEQ ID NO:21 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, or a) a DNA having the nucleotide sequence of SEQ ID NO: 21, b) a DNA encoding a protein having AmtR activity and being hybridizable with the nucleotide sequence of SEQ ID NO:21 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C, or (v) enhancing expression of a gene encoding glutamine synthetase by replacing an expression regulatory sequence with a stronger one, a) a. protein encoded by a DNA having the nucleotide sequence of SEQ ID NO: 15, b) a protein having arginine repressor activity and being encoded by a DNA that is hybridizable with the nucleotide sequence of SEQ ID NO:15 under stringent conditions comprising washing at 0.1 x SSC, 0.1 % SDS, at 60°C.