We proposed two-channel type holographic diversity interferometry (2ch-HDI) for highly accurate of phase modulated signals. In the 2ch-HDI, two phase-shifted interference patterns between signal beams and reference beams are simultaneously generated by utilizing the characteristics of polarization. These two interference patterns are captured by two image sensors, which are allocated in different places. Obtaining these interference data, the phase distribution of signal beam is calculated by the optimum algorithm for 2ch-HDI. In this paper, we demonstrated an experiment to verify the basic operation of 2ch-HDI. We also reported the simulation result for evaluating the measuring accuracy of the 2ch-HDI.