Federal prosecutors say 34-year-old Stephen Gurule entered his plea Friday.
He was arrested in October on a criminal complaint charging him with robbing the Community Bank on Sept. 27.
Authorities say a man passed a handwritten note demanding money to a bank teller.
In early October, the FBI received information that Gurule had confessed to robbing a bank in Espanola.
The agency compared a driver's license photograph of Gurule to the robber shown on the bank surveillance video and determining that the robber appeared to be Gurule.
Gurule has been in federal custody since his arrest and remains detained pending his sentencing hearing, which has yet to be scheduled.