The present invention relates to an apparatus for assisting muscular strength which assists joint movement of the leg joint part of a user, having a first bone part, a second bone part connected to the first bone part through a first joint, and a third bone part connected to the second bone part through a second joint. The apparatus for assisting muscular strength comprises: a first wire coupling member which is worn on the second bone part； a first wire whose one end is fixed to the first wire coupling member； a first wire guide which guides the movement of the first wire； a second wire coupling member which is worn on the third bone part； a second wire whose one end is fixed to the second wire coupling member； a second wire guide which guides the movement of the second wire； and a bearing capacity generator. The bearing capacity generator includes: a base frame； a rotary body which is installed to the base frame to be able to rotate； a wire reel which is coupled to the rotary body so that the first wire can be wound； a wire support spring which provides elastic force to the rotary body to rotate the rotary body in a direction in which the first wire is wound； and a torque adjuster which is installed to the rotary body to be connected to the wire support spring so as to adjust torque generated by the wire support spring with respect to the rotary body by changing the radius to which the elastic force of the wire support spring is applied with respect to the center of rotation of the rotary body according to the movement of the second wire.본 발명에 따른 근력 보조장치는, 제 1 뼈대부와, 제 1 뼈대부와 제 1 관절을 통해 연결되는 제 2 뼈대부와, 제 2 뼈대부와 제 2 관절을 통해 연결되는 제 3 뼈대부를 갖는 사용자의 다관절부에서의 관절 운동을 보조해주기 위한 것으로, 제 2 뼈대부에 착용되는 제 1 와이어 결합부재와, 일단이 제 1 와이어 결합부재에 고정되는 제 1 와이어와, 제 1 와이어의 움직임을 가이드하는 제 1 와이어 가이드와, 제 3 뼈대부에 착용되는 제 2 와이어 결합부재와, 일단이 제 2 와이어 결합부재에 고정되는 제 2 와이어와, 제 2 와이어의 움직임을 가이드하는 제 2 와이어 가이드와, 지지력 발생기를 포함한다. 지지력 발생기는, 베이스 프레임과, 베이스 프레임에 회전 가능하게 설치되는 회전체와, 제 1 와이어가 감기도록 회전체에 결합되는 와이어 릴과, 제 1 와이어가 감기는
