What is required is a method of producing, without treating a glycoprotein in a biological sample with a denaturing agent in advance, a selectively binding material, which specifically reacts with a glycan of a glycoprotein, a selectively binding material such as antibody thus produced by the method, and a method of specifically detecting a glycoprotein by using the selectively binding material.

In order to solve the problems, the present invention produces a selectively binding material specifically reactive with a glycan of a glycoprotein by treating the glycoprotein with a glycan-specific glycan-cleaving enzyme.