The present invention relates to a plastic lens comprising a multilayer antireflective film and to a method for manufacturing the same. The plastic lens has a multilayer antireflective film present on the surface of a plastic lens substrate, either directly or through another layer. The multilayer antireflective film comprises a composite layer in which at least two metal oxide layers, containing an identical metal element but different quantities of oxygen, are adjacent. In the method for manufacturing the above plastic lens, each of the metal oxide layers constituting said composite layer is formed by employing a single vaporization source and by vapor depositing adjacent layers under differing conditions of partial pressure of reactive oxygen gas.