PROBLEM TO BE SOLVED: To provide a muscular strength assisting device that can increase a bending angle of a second wearing device relative to a first wearing device.SOLUTION: The muscular strength assisting device includes: a first wearing device 10 disposed along one bone of a joint a second wearing device 20 disposed along the other bone of the joint and an artificial muscle 30 with one end 31 provided on the first wearing device 10 and the other end 32 provided on the second wearing device 20. The device is provided with an assist artificial muscle 50 for supporting the movement of elbows, knees, or wrists of a user and attached at one end 51 thereof to the first wearing device 10. The other end 52 of the assist artificial muscle 50 is connected via a swing arm 40 to one end 31 of an artificial muscle 30, and the one end 31 of the artificial muscle 30 is made displaceable relative to the first wearing device 10 by the assist artificial muscle 50.
