AbstractMany active safety technologies for the driver support system are developing. Most traffic accidents are caused by the driver's inattentiveness or drowsiness. We are developing a driver support system that protects against traffic accidents due to these causes. Our purpose is to detect the driver's face region with a camera. Many face detection methods are proposed, but there is no technique addressing every environment inside the car. For example, skin color segmentation cannot detect the skin region in the night, because it has to light up the driver by bright light. In this paper, we propose a skin detection method using the unique reflection characteristics of the materials. Our method is a very simple algorithm. We developed a skin detection system, and confirmed its effectiveness by an evaluation experiment in an indoor environment, and showed its effectiveness by a nighttime driving experiment. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(11): 19–27, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10149