An object of the present invention is to provide a buffered optical fiber, which excels in environmental characteristics and mechanical characteristics and has high flame retardancy and excels in optical transmission characteristics, and to provide a buffered optical fiber, which is terminated with a connector and uses this buffered optical fiber. The buffered optical fiber of the invention is provided with a second coating layer on an outer peripheral surface of an optical fiber produced by providing a first coating layer on an outer peripheral surface of a glass fiber. A second resin composition constituting the second coating layer comprises 100 to 250 weight parts of metal hydroxide and 10 to 100 weight parts of a nitrogen-based flame retardant material per 100 weight parts of the base polymer. Further, the second resin composition does not contain halogenated materials.