When he was born, the Imagawa clan had been already expelled from Suruga Province by Shingen TAKEDA, and Norimochi was said to be born in Odawara, the home ground of the Gohojo clan which was his mother's family.
誕生当時、既に今川氏は武田信玄によって駿河国を追われており、範以も母方の後北条氏の本拠小田原で生まれたという。