By employing a dual-chirped optical parametric amplification (DC-OPA) using MgO:LiNbO₃ crystals, we generate 31 mJ mid-infrared (MIR) pulses at 3.3 um with a repetition rate of 10 Hz. After passing through a CaF₂ bulk compressor which has 70% throughput efficiency, these MIR pulses are compressed to 70 fs (6.3 optical cycles), which is close to the transform-limited duration of 66 fs. Thus, the peak power is evaluated to be 0.3 TW. Our results present notable progress in the generation of high-energy MIR pulses and prove that DC-OPA is a superior method for efficiently generating MIR pulses with few-cycle duration and TW-class peak power.