A new electro-optic modulator for compensating the nonlinear distortion is proposed. The third-order intermodulation distortion (IMD3) induced in the receiver output are optically suppressed by using two Mach-Zehnder modulators (MZMs) connected in parallel and operating with chirp-parameters of the opposite signs to each other. The performance of the IMD3 compensation was estimated by the numerical calculations. We made an experiment to confirm the IMD3 compensation operation by using 10 GHz two-tone microwave signals and a 1.55 μm light source. The modulator was constituted by a dual-parallel Mach-Zehnder modulator (DPMZM). The chirp parameters of MZMs of the DPMZM were set to +0.5 and -0.5, respectively. It was observed by the measurement that the IMD3 components in the receiver output were suppressed by more than 20 dB compared to those for the conventional single-MZM operation in a range of modulation index below 0.25π rad. These experimental results agree well with the numerical calculation ones.