Abstract: An objective of the present invention is to provide a caged compound that can be photoactivated selectively for specific target cell types and can be used in an individual organism. The objective can be achieved by a compound represented by general formula K-Q-X, which is prepared by binding bioactive substance X, photocleavable protecting group Q, and compound K, which can be an enzyme substrate and is dissociated from Q-X by an enzyme reaction, wherein: Q is a protecting group that is photocleaved by light with a specific wavelength and then dissociated from X, when K is not bound thereto; X is a substance that does not express bioactivity when Q is bound thereto, but expresses bioactivity when Q is dissociated therefrom; and K is dissociated from Q by the above enzyme, so as to form a compound represented by Q-X.