<p>Disclosed are: a novel monoclonal antibody which is specific to a neoepitope located on the C-terminal side of a collagen fragment, wherein the binding affinity achieved when proline contained in the neoepitope has a non-hydroxide form and the binding affinity achieved when proline in the neoepitope has a hydroxide form are substantially same as each other; and an immunoassay, a measurement method, a kit and the like each utilizing the monoclonal antibody. The monoclonal antibody enables the quantification of a collagen fragment produced as the result of the digestion of a biological sample with a collagenase regardless of the presence or absence of a hydroxide form of proline in the neoepitope.</p>
