The present invention provides a plastic optical component. The plastic optical component has superior characteristics including lightweightness, low cost and suitability for mass production. The plastic optical component exhibits superior moisture barrier quality while experiencing no uneven refractive index profile in their interior even if they are subjected to the effect of water in the environment. An organic-inorganic hybrid layer obtained by a sol-gel process is formed as a moisture-proof coating at least on the surfaces of the plastic optical component's body which are in contact with the outside air.