Abstract: An objective of the present invention is to provide antigen-binding molecules whose antigen-binding activity changes depending on the concentration of a small molecule compound specific to a target tissue, polynucleotides encoding the antigen-binding molecules, vectors containing the polynucleotides, cells carrying the vectors, libraries containing a plurality of the antigen-binding molecules that are different from one another, pharmaceutical compositions containing the antigen-binding molecules, methods of screening for the antigen-binding molecules, methods of producing the same, and the like.