The effect of the hydrophobicity of gel chains on the volume changes of ionic gels in binding of the Dodecylpyridinium (DP) ions was examined. The study was carried out for a series of copolymer gels, acrylate-methylacrylate, acrylate-ethylacrylate, acrylate-n-propylacrylate, and acrylate-n -butylacrylate(BA), in which the molar ratios of acrylate to the alkyl acrylate were 1. The distinctive two regimes; the regime HYS where the volume changes with hysteresis and the regime TRL where it changes in a transition-like manner without hysteresis, were found in the volume change with the concentration of DP ion (C-out). The hysteresis was more prominent for the more hydrophobic gel and/or the gel in the solution of lower salt concentration. Substantial plateau regions were found between HYS and TRL in the volume change of the more hydrophobic gel. The hysteresis was also exhibited for the change in degree of binding of counterion, beta, with C-out. The dissociation rate of DP ion in immersing the gel bound by DP ions into the solution of higher salt concentration is affected by the hydrophobicity of gel chain more than by the osmotic pressure.