We have been developing a pneumatic total artificial heart (PTAH) system which was driven by a wearable pneumatic drive unit (WPD). The WPD which have driven one blood pump by one actuator, called as WPD100, had problems such as high power consumption, large size and excessive negative air pressure. To solve these problems, we developed a WPD twin head type (WPD TH) equipped with a mechanism to drive two pumps by one actuator and relief valves to avoid excessive negative pressure. In this study, we evaluated the performance and characteristics of the WPD TH in a mock circulation test and numerical calculation. As a result, the maximum flow rates of the left and right pumps driven by the WPD TH were 7.9 L/min and 9.3 L/min even under the pressure release in diastole. The maximum power consumption and the efficiency were 27.6 W and 6.6% in the case of right and left pumps driven from side to side, and these were improved in comparison with WPD100. The alternate drive method had advantages of suppressing vibration and a mechanical load in the numerical calculation. These results indicated that the WPD TH had a basic performance to realize a wearable PTAH system.