Optical fiber and optical fiber ribbon

The present invention relates to an optical fiber housed within the fiber-optic cable, in particular, the optical fiber coating resin and the colored resin optimizing, used by the environment or aging, the optical fiber center with a suppressed transmission loss increase of the optical fiber It relates lines, use environment and aging, in particular, optical fiber transmission loss does not increase when exposed under water or high humidity, there is provided an optical fiber ribbon. Optical fiber according to the present invention is an optical fiber coated with the coating resin of at least two layers, said coating resin being most covered on the outside is a colored layer made of colored resin, the optical fiber center dissolution rate of the coating resin from the optical fiber is set to 1.5 mass% or less line to when immersed for 168 hours to the heated water 60 ° C..