Detection of skin region is one of the important process of the face detection. Skin region is usually detected by using
the skin color. However, the method has some problems which are influence of lighting condition and etc. The methods
are defined the skin color in visible optical band. The method should illuminate visible light in the dark place. Therefore
we paid attention to difference of the reflectance characteristic of materials. We proposed a skin detection method
directly by the reflection characteristic. In this paper, we propose a method to reduce influences of the environment light
by using one band pass filter. The usefulness is confirmed by a skin detection experiment.