In order to realize a power assisting suit for assisting a nurse caring a patient in her arm, a hardness sensor of muscle using load cell and a pneumatic rotary actuator utilizing pressure cuffs have been developed. The power assisting suit consists of shoulders, arms, waist and legs made of aluminum, and is fitted on the nurse body. The power assisting suit is originated with the concept of a master and slave system in one body. The arms, waist and legs have the pneumatic rotary actuators. The pneumatic rotary actuators are constructed with pressure cuffs sandwiched between thin plates. The action of the arms, waist and legs of the nurse are sensed with the muscle hardness sensor utilizing load cell with diaphragm mounted on a sensing tip. The dent of the sensing tip corresponds to the hardness of the muscle so that exerting muscle force produces electric signal. This paper gives the design and characteristics of the power assisting suit using the cuff type pneumatic rotary actuators and the muscle hardness sensor verifying its practicability.