The salt effects on the volume phase transition of ionic poly(acrylate) gel with a change in the concentration of hydrophobic counterion, dodecylpyridinium chloride (DPC) in outside solution of the gel is investigated. The transition concentrations increase with the NaCl concentration C-s of the solution and the transition disappears at C-s above 0.5 M. A hysteresis is observed for the transition concentration of DPC; that is, the deswelling transition concentration in the increasing process, C-t(i) is significantly higher than the swelling transition concentration in the decreasing process C-t(d). The difference between C-t(i) and C-t(d) is found to increase with decrease in C-s. The comparison of the gel and the polymer solution reveals the resemblance between the salt effects on their phase transitions.