A man walked into the Sturgis Bank and Trust branch on South Centreville Road and displayed a weapon as he demanded money.
He made off with an undisclosed amount of cash in the 10:25 a-m robbery.
Sturgis Police say the suspect was a black male, 5-feet-7-inches and thin build. He was wearing baggy clothing that included blue jeans, a black hoodie with an unusual design on the back, a blue bandana and dark sunglasses.
Sturgis Bank and Trust is offering a reward for information leading to the apprehension of the robber.
Anyone with information should call St. Joseph County Dispatch at 269-467-4195 or Crimestoppers at 800-342-STOP.