To provide a new reductive-stimuli-responsive degradable gel that allows any control of decomposition of the three-dimensional base material for cell culture and production of a completely biological three-dimensional cellular structure consisting only of cells and cells-produced extracellular matrix and that allows safe recovery of the cellular structure produced.A stimuli-responsive hydrogel, characterized by being produced by crosslinking a water-soluble polymer with a compound having a disulfide bond in the molecular chain.
