Silica sols are produced by the neutralization of sodium silicate with sulfuric acid. The produced silica sols gradually increase in viscosity and finally form gels through a sol-gel transition in which the pH of the sols strongly influences the gelation time. In this study, the rheological property of silica gels produced from alkaline sol was evaluated experimentally in comparison with that obtained from acid sol. Dynamic viscoelastic measurements, creep tests, and morphological measurements were conducted to compare the alkaline sol with the acid sol. The different properties of the gels may be related to the bonding manner and/or the sizes of the silica particles that form the network structure within the gels. The particle-bonding models are presented in this study.