To provide a roller chain of high reliability in the atmosphere of high temperature and corrosive fluorine gas.

A roller chain has a roller link 10 with a roller 11, and a pin link 20 with a pin 21 piercing the roller 11. A bush 12 for inserting the pin 21 through is provided on the inside of the roller 11. The bush 12 has an uniform inner diameter part positioned on the inside, and gradually increased inner diameter parts with the inner diameter gradually increased toward both end opening parts from the uniform inner diameter part. The bush 12 is formed of a Co group alloy containing Cr at 25.0-33.0wt.%, W at 3.0-14.0wt.% and C at 0.9-3.0wt.%.