The present invention relates to a process for producing amino acid derivatives such as optically active β-amino acid in short steps with good yield and high optical purity, which comprises reacting a keto acid of the formula (1): wherein R1 is hydrogen, an optionally substituted hydrocarbon, etc.; R2 is a spacer; and R3 is an optionally substituted alkoxy, etc., or a salt thereof, with ammonia or an amine or a salt thereof in the presence of a chiral catalyst and in the presence or absence of an acid and/or a fluorine-containing alcohol, to give an amino acid derivative of the formula (2): wherein Q is a group formed by removing one hydrogen atom from ammonia or an amine; X′ is an acid and/or a fluorine-containing alcohol; and b is 0 or 1.