Multiple phase shift keying technology is effectively used in various communication systems because of its high-capacity data transmission capability along a restricted passband. This-paper proposes a high-performance offset quadri-pulse shift keying modulator and demodulator with a new simple circuit configuration employing surface acoustic wave (SAW) devices. We propose two types of modulators (modulation and pulse pattern generation method) and a demodulator with a differential-operation SAW device. A fundamental experiment verified the feasibility of the circuits.