The present invention provides a modified ethylenediamine-N,N'-disuccinate:ethylenediamine lyase. The present invention also provides a protein that comprises the amino acid sequence represented by SEQ ID NO: 1; or a protein that comprises an amino acid sequence derived from the amino acid sequence represented by SEQ ID NO: 1 by deletion, substitution, or addition of one or more amino acid residues, and has an ethylenediamine-N,N'-disuccinate:ethylenediamine lyase activity.