We report the dynamics of the rapid responsive chemomechanical gel device caused by changes in the properties of the solvent. The swelling processes are well described by the Tanaka-Fillmore (TF) theory. However, we found that there are distinct discrepancies in the relaxation times between the swelling and shrinking processes to the same final state, even though this gel has no surface skin layer in the shrinking process. The shrinking process reflects detailed features of the diffusion process which are hidden during the swelling process. We also consider the conditions under which the TF theory is valid in the shrinking process. © 1995 The Japan Society of Applied Physics.