The tensile moduli of poly(acrylate) gel collapsed due to the hydrophobic dodecylpyridinium(DP) ion binding in the various salt concentrations were measured. It was found that the tensile force relaxed after the elongation and that the relaxation moduli strongly depended on the salt concentration, C-S. The differences between the moduli at initial, Y-i, and at equilibrium, Y-e, were 4 x 10(5) Pa at C-S = 10 mM and 3 x 10(3) Pa at C-S = 100 mM. The substantially constant moduli, (Y-i similar to 5 x 10(5) Pa and Y-e similar to 4 x 10(4) Pa) at C-S between 10 and 50 mM deeply drop at C-S between 80 and 100 mM, and level off (Y-i similar to 11 x 10(3) Pa and Y-e similar to 8 x 10(3) Pa) at C-S above 100 mM. However, the size of gel at C-S = 100 mM is essentially the same as that at C-S = 10 mM. This indicates that the C-S-dependent attraction between the ionic network and the hydrophobic counterions seriously affects the elasticity of the collapsed gel system. The relaxation moduli, Y(t), of the gel is fitted to a function of Y(t) = (Y-i - Y-e){alpha(1)e(-t/tau1) + alpha(2)e(-t/tau2) + (1 - alpha(1) - alpha(2))(1 + t/tau(0))(-beta)} + Y-e.