PROBLEM TO BE SOLVED: To provide a power assist suit capable of achieving smooth walking regardless of the mass of a leg unit of the power assist suit, and to provide a control method of the power assist suit.SOLUTION: In a control method of a power assist suit, an acceleration track for a foot part in an idling leg period is generated based on acceleration data of the foot part in the idling leg period obtained by at least one sensor, and a target torque for each of a first actuator and a second actuator is set based on the acceleration track and the mass of a leg unit, and each torque generated by each of the first actuator and the second actuator is controlled based on the target torque.SELECTED DRAWING: Figure 6