was a town located in Oda District, Okayama Prefecture, Japan.
As of 2003, the town had an estimated population of 5,421 and a density of 74.57 persons per km<sup>2</sup>. The total area was 72.70 km<sup>2</sup>.
On March 1, 2005, Bisei, along with the town of Yoshii (from Shitsuki District), was merged into the expanded city of Ibara.
Bisei was known for the Bisei Spaceguard Center.