The Miyagase Dam (宮ヶ瀬ダム, Miyagase damu) is a dam on the Nakatsu River, a main tributary of the Sagami River in Aikō District, Kanagawa Prefecture, Japan.

Work on the Sagami Dam, the first dam on the main stream of the Sagami River began in 1938; however, lack of funding and the advent of World War II delayed completion until after the end of the war.

The growth in population of nearby Atsugi and increased need for industrial and drinking water spurred plans for additional dams on the Sagami River's tributaries.

It was designed and built by a consortium of the Kajima Construction, Obayashi Corp. and the Toda Corporation.

[1] The reservoir created by the dam, Lake Miyagase (宮ヶ瀬湖, Miyagase-ko) is a popular recreation spot in Kanagawa Prefecture.