The effect of plasticizer content on the magnetic-field sensitivity for magnetic elastomers has been investigated while maintaining the concentration of magnetic particles at 70 wt %. The magnetic-field dependence of the storage modulus for magnetic elastomers was measured by dynamic viscoelastic measurements under magnetic fields with a sweep rate of 3.7 mTs(-1). The magnetic-field sensitivity, determined by the initial slope of the storage modulus using an exponential function, increased from 1.0 x 10(-3) to 1.8 x 10(-2) mT(-1) with increasing plasticizer content.