- Death: 1604
- Distinction: Uesugi retainer
- Title: Ômi no Kami
- Other name: Amakusa Nagashige
- Amakusa clan of Echigo
Kagemochi served Uesugi Kenshin and later Uesugi Kagekatsu. He held Masugata castle in northern Echigo province. He gained fame at the 4th Battle of Kawanakajima (1561) for commanding the rear guard that attempted to hold off a Takeda force under Kosaka Masanobu and Baba Nobufusa while the main Uesugi army attacked Takeda Shingen - a stand that earned him praise from friend and foe. He was later active in the war with the Oda and was still alive when the Uesugi were moved to Aizu after Sekigahara (1600).