Provided is a plastic optical fiber which has low transmission loss and low bending loss, does not undergo the occurrence of cracking upon being stretched, can be molded under a wide range of molding conditions, and can be produced using an amorphous fluorinated polymer. A plastic optical fiber provided with an inner layer, an outer layer that has a lower refractive index than that of the inner layer, and a protective coating layer that coats the outer periphery of the outer layer, wherein the inner layer contains an amorphous fluorinated polymer (a) having no C-H bond, the outer layer contains an amorphous fluorinated polymer (c) optionally having a C-H bond only at the terminal of the main chain thereof, the glass transition temperature of the fluorinated polymer (c) is equal to or higher than the glass transition temperature of the fluorinated polymer (a), the plastic optical fiber has a stretched form, and the percentage of elongation at break of each of the fluorinated polymers (a) and (c) is 120% or more and is larger than the stretching magnification of each of the fluorinated polymers (a) and (c).