Recently, it is required to be earth-friendly for automotive industry. Especially, the reduction of CO2 emission and the cleaning of auto-emission are important issues. The development of new system and technology are being carried out to solve the issues. The vehicle weight reduction is one of the most important technologies. Magnesium, the lightest practical metal, is so probable for the weight reduction that many researchers are working on the practical application of magnesium. In this paper, the advantages and problems of magnesium use in automotive parts are overviewed with practical examples of TOYOTA. And also, some suggestions are presented for the further increase of magnesium automotive parts.