Nursing care is a very important job for helping person to regain health or achieve the quality of life. Many nursing-care assistant robot and device have been developed in recent years. In this presentation, I will introduce a nursing-care assistant robot (Robear) we developed when I worked in RIKEN. This robot was successful in lifting patient up and transferring him/her between bed and wheelchair using its two human-like arms. In order to lift up patients comfortably and automatically, I proposed a motion generation method by reducing patient's load and pain feeling during lifting-up. In this method, the contact force and muscle force can be estimated using a human-robot model. We also measured the stiffness of human body for reducing the pain feeling. The effectiveness of this method has also been verified in experiment. In this presentation, I will also introduce this method and show the experiment and the result.