Nichihara (日原町 Nichihara-chō) was a town located in Kanoashi District, Shimane Prefecture, Japan.
As of 2003, the town had an estimated population of 4,255 and a density of 25.44 persons per km². The total area was 167.24 km².
On September 25, 2005, Nichihara was merged into the expanded town of Tsuwano.
The town has a sky observatory which once had one of the biggest lenses in Japan.
The Takatsu river runs through the town and in the summer season fishermen catch Ayu fish, a local delicacy. It is said to be the cleanest river in Japan, thus producing said Ayu fish.