Mount Aka (赤岳, Aka-dake) is a 2,899m mountain on the border of Chino, Hara of Nagano, and Hokuto of Yamanashi in Japan.

Mount Aka is a stratovolcano.

This mountain is a center of the Yatsugatake-Chūshin Kōgen Quasi-National Park.

There are several routes to reach to the top of Mount Aka.

It takes about four and half hours.