The purpose of the research was influential in the fashionable decolleti of women`s costume in the mid-15th century. The results were as follow: A variation of social environment and an aesthetic sense brought on desires to express human nature. Especially, the importance for costume of the appearance of a new spirit, confirmed and developed on the contemporary. The first symptoms of humanism were leaning towards secular art, an ideal of man at once more independent and avid for action, and an interesting applied to the individual and particularity. In addition, love affairs between the ladies and knights led to increasing interest in the beauty of weakness and tenderness in the women`s body. Sorel Agne`s who was a `lover of Charles VII, France king, had a great influence on the fashion of de＇collette＇ in women`s costume. It was just a de＇collette＇ to express an ideal of beauty to neckline in women`s dress in contemporary.