An analysis method is provided, by which it is determined whether or not a solution to be examined contains an organic substance in an amount on the order of 20 mass ppb or less. The analysis method for organic substances in a solution to be examined includes the following steps: a sampling step in which 500 ml or less of a sample solution is taken from a solution to be examined; an adsorption step in which the sample solution is passed through activated carbon 8 so that the organic substance is adsorbed on the activated carbon; an extraction step in which the organic substance is extracted into a hydrophobic solvent; a specimen preparation step in which, a specimen solution is prepared by using the hydrophobic solvent into which the organic substance has been extracted; and an analysis step in which an analysis is performed to determine whether or not the organic substance in an amount of 20 mass ppb or less is contained in the solution to be examined. The activated carbon 8 has a specific surface area of 800 m 2 /g or more, and the amount of the activated carbon 8 is 0.025 g/ml or more relative to the amount of the sample solution. In the adsorption step, the sample solution is passed at a rate of 7.5 ml/min or less on the discharge side of the activated carbon 8.