This paper describes a new scan matching method for mobile robot localization and mapping. The proposed method "Intensity-ICP" uses Laser Reflection Intensity obtained by u laser range scanner named "SOKUIKI sensor". Compared with conventional scan matching methods which are effective just in geometric featured environments, Intensity-ICP is effective in both geometric featured and featureless environments if there are some features like colors or materials. This method can build a map with Laser Reflection Intensity data. The map will be effective to robust localization because it has abundant information; not only geometric data but also Laser Reflection Intensity.