PROBLEM TO BE SOLVED: To provide novel microorganisms of Clostridium chromoreductans ER-CL-1 (an accession number of NITE P-1434) and a method for degrading a metal cyano complex capable of effectively degrading and removing a metal cyano complex from waste water and soil which may contain an iron cyano complex.SOLUTION: Novel microorganisms having the ability to degrade an iron cyano complex and at least one kind of facultative anaerobic microorganism selected from microorganisms belonging to genus Klebsiella and genus Enterobacter are cultured in a culture medium containing a metal cyano complex.