To provide a practical technique for assisting the lower body of a subject by internally rotating thigh muscles. A lower body assisting device includes a right leg strap 10R for internally rotate right thigh muscles, a left leg strap 10L for internally rotate left thigh muscles, and a waist/hip strap 20 linking them to each other. Both ends of the waist/hip strap 20 is connected to the back sides of the right and left leg straps 10R and 10L, respectively.
