In this paper, we show the performance characteristics of two kind of pneumatic actuators fabricated a foam lost molding method. One is pneumatic actuator using positive pressure, and the other is one using negative pressure. The former actuators were driven by applied positive pressure, but actuator using the low degree of rubber hardness was broken when the applied pressure was 30 kPa, because the strain of actuator was larger than the breaking strain of tensile strength test of rubber. The displacement of later actuator was in proportional of the applied negative pressure, but the displacement was maximum when applied pressure was -60 kPa.