It is important that we maintain a comfortable residential environment for health care. In this paper we use PMV (Predicted Mean Vote) as a measure of thermal environment. To calculate PMV, we need to get air temperature, radiant temperature, air velocity, and air humidity as environmental parameters. We also need to get metabolic rate and clothing insulation as a factor of human. The robot measures the air temperature, air humidity and the clothing insulation. For measuring the clothing insulation, we detect skin and clothes regions in a FIR image and estimate the average temperature of the skin and the clothes surface. We carried out experiment of estimating clothing insulation using far infrared camera and thermal environment evaluation using mobile robot.