Abraham A. Rojas Jr., 18, was arrested at about 5 a.m. Sunday at a house near the intersection of East Chicago Street and North Kimball Avenue, Caldwell police said.
A man wearing a skull mask and carrying a large knife robbed a Subway at 319 N. 10th Ave. at 9:45 p.m. Friday.
The robber threatened shop employees and fled with an undisclosed amount of money.
No one was injured in the incident.
Police received a tip that the suspect could be found at a home in the 800 block of East Chicago.
Rojas was taken into custody without incident. Police said they recovered a knife, mask and other clothing that matched that worn by the robber.
Rojas was taken to the Canyon County Jail. He was charged with robbery.