He became the family head at the age of 14 in 1507 due to the death of his father, he exterminated Nobushige TAKEDA, his uncle who was against, in the Battle of Bomine (Fuefuki City, Yamanashi Prefecture and former Sakaigawa-mura, Higashiyachiyo County).
永正4年（1507年）、父の病死により14歳で家督を継ぐと、永正5年（1508年）には対立していた叔父の武田信恵を坊峰合戦（笛吹市、旧東八代郡境川村）で滅ぼした。