A wearable assistive device may include a main frame provided on a user's waist, a leg assembly that extends from an end of the main frame, and an optional foot support installed at an end of the leg assembly to support the user's foot. The leg assembly may include a leg frame having a first end connected to the main frame and a second end connected to the foot support, and a leg belt mounted on the leg frame. The leg belt may include a belt to secure a leg of the user and a wire winding structure that may include a wire connected to a first end of the belt and a wire winding dispenser on which the wire is wound and which fixes or releases a second end of the belt.