To provide a method for processing the end face of a plastic optical fiber by which method optical transmission loss is suppressed and the processing is carried out efficiently.

The method is employed in which the core 7 of a plastic optical fiber 2 is formed with a material having a glass transition point lower than the melting point of a clad 8 and in which an end face processing is carried out by pressing the end face 3 of the plastic optical fiber 2 against the surface 6 of a hot plate 5 mirror-finished and heated on the basis of the glass transition point. In addition, as included in the method, the plastic optical fiber 2 projected from the tip end 4 of a ferrule 1 is machined, with the end face 3 of the plastic optical fiber 2 brought extremely close to the tip end 4 of the ferrule 1, and then, the end face processing is performed by pressing the end face 3 against the surface 6 of the hot plate 5.