The roles of ionic bonding in molten ethylene ionomers without ionic aggregates were theologically characterized in linear and nonlinear regions under shear. We have measured melt rheology of ethylene-methacrylic acid (EMAA) ionomers by means of dynamic shear, step-shear relaxation, and transient shear viscosity. The studied samples were EMAA copolymer (MAA = 5.4 mol %), its sodium and zinc ionomers, in both of which the neutralization degree of total MAA is 20%, where no ionic aggregates exist. The dynamic shear properties revealed that the time-material superposition, i.e., the super-master curve, was applicable among the three samples, suggesting that the ionic bonding only acts as the increase of polymeric chain friction in the linear region. The damping functions from the step-shear relaxation were found to be identical to one another among the three, resulting in that the effect of ionic bonding does not appear. However, the damping property of the zinc ionomer, which was analyzed by the Bemstein-Kearskey-Zapas (BKZ) model in the start up of steady shear viscosity, exhibited unexpectedly much weaker than those of EMAA and the sodium ionomer. It is the first observation that the influence of pseudo cross-linking structure from ionic bonding clearly appears in experimental theological studies of ethylene-ionomer melts.