Fifteen species of wild mushrooms, which are classified as edible, medicinal, poisonous, or unknown types, were analyzed for their free amino acid contents. The average total amino acid content was 1,120.0 mg/kg in the edible type, 1,037.8 mg/kg in the medicinal type, and 1,010.8 mg/kg in the poisonous or unknown type, respectively. The edible type wild mushrooms showed the highest average content of total essential amino acids; conversely, the poisonous or unknown type showed the lowest content. Leucopaxillus giganteus (OK811) showed the highest total amino acid (1,212.4 mg/kg) and essential amino acid (490.2 mg/kg) contents among edible type, while Pycnoporus sanguineus (OK1071) showed the highest total amino acid (1,233.7 mg/kg) and essential amino acid (412.8 mg/kg) contents among the medicinal type. Among the poisonous or unknown type, Hypholoma fasciculare (OK826) showed the highest total amino acid (1,223.4 mg/kg) and essential amino acid (442.8 mg/kg) contents. The amino acid contents of wild mushrooms are fundamental data for the screening of useful genetic resources with nutritionally superior properties.