A production method of glycolic acid, which comprises: a first step of obtaining an aqueous glycolonitrile solution from formaldehyde and hydrocyanic acid, a second step of treating the aqueous glycolonitrile solution of the first step so that the glycolonitrile is hydrolyzed into a glycolate salt, and a third step of obtaining glycolic acid from the glycolate salt, wherein the aqueous glycolonitrile solution obtained in the first step is stored at pH 4 or less and the hydrolysis reaction of the second step is performed at a pH in the range of from 5 to 9, and wherein a microbial enzyme having a hydrolytic activity of a nitrile group is used for the hydrolysis reaction of the glycolonitrile and said microbial enzyme is produced by Acinetobacter sp; or which comprises: a first step of obtaining an aqueous glycolonitrile solution from formaldehyde and hydrocyanic acid, and a second step of treating the aqueous glycolonitrile solution of the first step so that the glycolonitrile is hydrolyzed into glycolic acid, wherein the aqueous glycolonitrile solution obtained in the first step is stored at pH 4 or less and the hydrolysis reaction of the second step is performed at a pH in the range of from 5 to 9, and wherein a microbial enzyme having a hydrolytic activity of a nitrile group is used for the hydrolysis reaction of the glycolonitrile and said microbial enzyme is produced by Acinetobacter sp. a first step of obtaining an aqueous glycolonitrile solution from formaldehyde and hydrocyanic acid, a second step of treating the aqueous glycolonitrile solution of the first step so that the glycolonitrile is hydrolyzed into a glycolate salt, and a third step of obtaining glycolic acid from the glycolate salt, wherein the aqueous glycolonitrile solution obtained in the first step is stored at pH 4 or less and the hydrolysis reaction of the second step is performed at a pH in the range of from 5 to 9, and wherein a microbial enzyme having a hydrolytic activity of a nitrile group is used for the hydrolysis reaction of the glycolonitrile and said microbial enzyme is produced by Acinetobacter sp; or which comprises: a first step of obtaining an aqueous glycolonitrile solution from formaldehyde and hydrocyanic acid, and a second step of treating the aqueous glycolonitrile solution of the first step so that the glycolonitrile is hydrolyzed into glycolic acid, wherein the aqueous glycolonitrile solution obtained in the first step is stored at pH 4 or less and the hydrolysis reaction of the second step is performed at a pH in the range of from 5 to 9, and wherein a microbial enzyme having a hydrolytic activity of a nitrile group is used for the hydrolysis reaction of the glycolonitrile and said microbial enzyme is produced by Acinetobacter sp. a first step of obtaining an aqueous glycolonitrile solution from formaldehyde and hydrocyanic acid, and a second step of treating the aqueous glycolonitrile solution of the first step so that the glycolonitrile is hydrolyzed into glycolic acid, wherein the aqueous glycolonitrile solution obtained in the first step is stored at pH 4 or less and the hydrolysis reaction of the second step is performed at a pH in the range of from 5 to 9, and wherein a microbial enzyme having a hydrolytic activity of a nitrile group is used for the hydrolysis reaction of the glycolonitrile and said microbial enzyme is produced by Acinetobacter sp.