One object is to ensure a moment of a desired magnitude for assisting in an activity of moving two body parts relative to each other, while keeping an output of an actuator low, the actuator generating a force at a point of action of the moment. A muscular strength assisting apparatus 1 includes a first assistance unit 10 having a first actuator 11 for changing a distance between a first body-side disposition portion 11A mounted to a first part of a body and a first outer-side disposition portion 11B separable from and contactable with the first body-side disposition portion 11A, and a second assistance unit 20 having a second actuator 21 for changing a distance between a second body-side disposition portion 21A mounted to a second part of the body and a second outer-side disposition portion 21B separable from and contactable with the second body-side disposition portion 21A. The muscular strength assisting apparatus 1 is mounted to the body so that a direction connecting the second body-side disposition portion 21A to the second outer-side disposition portion 21B is non-parallel to a direction connecting the first body-side disposition portion 11A to the first outer-side disposition portion 11B.
