Immobilization substrate and method for producing the same

A method for producing an antibody-fragment-immobilizing substrate comprising:

• contacting separate antibody fragments of at least two types that include at least one type of labeled antibody fragment having a labeled site labeled with a luminescent substance and at least one type of acceptor antibody fragment having an acceptor site for accepting emission from the labeled antibody fragment and that are capable of cooperatively recognizing one type of antigen, with the antigen, and forming a complex whereby each of the antibody fragments binds to the antigen;
• immobilizing the complex on a substrate via the antibody fragments in the complex;
• and
• removing the antigen from the complex to obtain the antibody-fragment-immobilizing substrate, wherein the antibody fragments are independently immobilized on the substrate in a positional relationship that allows each of the antibody fragments to bind to the same antigen.