Chitosan (CS) and poly(ethylene oxide) (PEO) are miscible with each other, because of the hydrogen bonding between CS and PEO that becomes stoichiometric at the PEO content of w_PEO = 20 wt%. This study analyzed the previously measured dielectric data of this stoichiometric CS/PEO blend being doped with two kinds of salt, potassium sulfate (K₂SO₄) and calcium sulfate (CaSO₄). Specifically, the casting solvent, acetic acid, was intentionally left in the blend to an amount almost equimolar to K and Ca, so that the doped blend contained two types of cations, H⁺ and K⁺ or Ca²⁺. The target of this study was to examine a synergetic effect of H⁺ and the metal cation, if any, on the dielectric behavior and ionic conduction. Comparison of the complex dielectric permittivity ε* of the K₂SO₄-doped and neat (undoped) blends suggested that K⁺ largely increased ε* by governing the electrode polarization at low frequencies (ω) and the hopping conduction at high ω. In contrast, doping of CaSO₄ considerably decreased ε* of the blend at low ω, even though the total concentration of the cationic species (H⁺ and Ca²⁺) was larger for the doped blend. This unusual, anti-synergetic effect was discussed in relation to constraint for the segmental motion of CS due to Ca²⁺ and the resulting suppression of segmental-motion-aided fast hopping and slow diffusion of H⁺.