An auto-analyzer of ω-amino acids has been set up by incorporating a reaction system of the phenol-sodium hypochlorite color reaction specific for ω-amino acids into a commercial, multi-line amino-acid analyzer. Conditions of the color reaction has been modified from those of ordinary test-tube reaction so as to obtain reproducible and highly sensitive analyses of ω-amino acids in biological materials by using this apparatus. As applications, free and bound-form ω-amino acids in some wild mushrooms have been analyzed and β-alanine formed by the action of aspartate α-decarboxylase on aspartic acid has been determined.