There was conflict between Nobuhiro and Nobunaga for a while such that, in 1556, Nobuhiro tried to take over Kiyosu-jo Castle in conspiracy with Yoshitatsu SAITO of Inaba-jo Castle in Mino province; however, he was later forgiven by Nobunaga.
その後、弘治_(日本)2年（1556年）に美濃国稲葉山城の斎藤義龍と組んで清須城乗っ取りを図るなど一時期は信長と対立するが、やがて許される。