A method for quantifying amino acids in a sample, comprising: Step comprising following steps: (Step 1-1) a step including a reaction (Reaction 1) wherein L-form and/or D-form amino acids (L-AA and/or D-AA) in the sample, an aminoacyl tRNA synthetase (AARS) corresponding to the amino acids and an adenosine triphosphate are reacted in the presence of a divalent ion or a polyamine to form a complex comprising an aminoacyl adenylate (aminoacyl AMP) and the AARS (aminoacyl AMP-AARS complex); (Step I-2) a step including a reaction (Reaction 2) wherein the aminoacyl AMP-AARS complex formed in Reaction 1 and/or Reaction 3 is reacted with a nucleotide to release the AARS and the amino acids (L-AA and/or D-AA) from the complex; (Step I-3) a step including a reaction (Reaction 3) wherein the amino acids (L-AA and/or D-AA) and/or the AARS released in Reaction 2 are reused in Reaction 1 to cause the aminoacyl AMP-AARS complex reaction; and (Step I-4) a step of repeating the Step I-2 and the Step I-3, and Step comprising measuring an amount of reaction products produced in the Step, wherein the molar number of the reaction products produced in Step is larger than that of the amino acids in the sample, and determining an amount of the L-form and/or D-form amino acids on the basis of the measured amount of the reaction products. Step comprising following steps: (Step 1-1) a step including a reaction (Reaction 1) wherein L-form and/or D-form amino acids (L-AA and/or D-AA) in the sample, an aminoacyl tRNA synthetase (AARS) corresponding to the amino acids and an adenosine triphosphate are reacted in the presence of a divalent ion or a polyamine to form a complex comprising an aminoacyl adenylate (aminoacyl AMP) and the AARS (aminoacyl AMP-AARS complex); (Step I-2) a step including a reaction (Reaction 2) wherein the aminoacyl AMP-AARS complex formed in Reaction 1 and/or Reaction 3 is reacted with a nucleotide to release the AARS and the amino acids (L-AA and/or D-AA) from the complex; (Step I-3) a step including a reaction (Reaction 3) wherein the amino acids (L-AA and/or D-AA) and/or the AARS released in Reaction 2 are reused in Reaction 1 to cause the aminoacyl AMP-AARS complex reaction; and (Step I-4) a step of repeating the Step I-2 and the Step I-3, and (Step 1-1) a step including a reaction (Reaction 1) wherein L-form and/or D-form amino acids (L-AA and/or D-AA) in the sample, an aminoacyl tRNA synthetase (AARS) corresponding to the amino acids and an adenosine triphosphate are reacted in the presence of a divalent ion or a polyamine to form a complex comprising an aminoacyl adenylate (aminoacyl AMP) and the AARS (aminoacyl AMP-AARS complex); (Step I-2) a step including a reaction (Reaction 2) wherein the aminoacyl AMP-AARS complex formed in Reaction 1 and/or Reaction 3 is reacted with a nucleotide to release the AARS and the amino acids (L-AA and/or D-AA) from the complex; (Step I-3) a step including a reaction (Reaction 3) wherein the amino acids (L-AA and/or D-AA) and/or the AARS released in Reaction 2 are reused in Reaction 1 to cause the aminoacyl AMP-AARS complex reaction; and (Step I-4) a step of repeating the Step I-2 and the Step I-3, and Step comprising measuring an amount of reaction products produced in the Step, wherein the molar number of the reaction products produced in Step is larger than that of the amino acids in the sample, and determining an amount of the L-form and/or D-form amino acids on the basis of the measured amount of the reaction products.