Provided is a production method of glycolic acid having a first step of preparing glycolonitrile from formaldehyde and hydrocyanic acid and a second step of hydrolyzing the glycolonitrile into glycolic acid directly or via a glycolate salt, which method can produce glycolic acid in easy production and purification steps while consuming less energy. In the production method, by carrying out the first and second steps continuously or by storing the glycolonitrile obtained in the first step at pH 4 or less and carrying out a hydrolysis reaction of the second step at from pH 5 to 9, a production yield of glycolic acid, activity for the production of glycolic acid and accumulated concentration of glycolic acid are improved, resulting in the production of glycolic acid having an improved purity and quality.