Japan's progressing aging society increasingly needs evaluation of equipment used for human assistance. Earlier studies have evaluated the use of wheelchairs. However, the manner in which the equipment moderates the generated consumption energy of helpers has not been described sufficiently. This study performs mechanical evaluation of a helper's walking using a wheelchair on a slope. We use the Musculoskeletal Model to estimate the joint moment and energy consumption. Results obtained with 14 volunteers who assisted these wheelchair experiments were considered for cases in which the energy consumption of the wheelchair increased by 13% from that of a normal gait when moving up an incline. This evaluation method is useful for developing practical assistance equipment.