A wearable action-assist device for assisting the wearer to act or doing an action for the wearer (1) comprises an action-assist wearable tool (2) having an actuator (201) to give the wearer a mechanical force, a biosignal sensor (221) for detecting a biosignal of the wearer (1), a biosignal processing means (3) for obtaining, from the biosignal (a) detected by the biosignal sensor, a neurotransmitting signal (b) to move the musculoskeletal system of the wearer (1) and a muscle potential signal (c) generated when a muscle activity occurs , a voluntary control means (4) for generating, using the obtained neurotransmitting signal (b) and muscle potential signal (c), a command signal (d) to generate a mechanical force reflecting the intention of the wearer (1) in the actuator (201), and a drive current generating means (5) for producing, according to the command signal (d), currents corresponding to the neurotransmission signal (b) and the muscle potential signal (c) respectively and supplying them to the actuator (201) ..