A method for manufacturing a plastic window includes a mold preparation step for preparing a first mold, a second mold, and a third mold, a film preparation step for preparing a functional film, a conductive portion, and a bus bar, a placement step for placing the functional film, a first injection step, wherein an intermediate product provided with the cover on the functional film in an integral manner is made, and a second injection step, wherein a product provided with the intermediate product on the second surface in an integral manner is made. The first mold surface has a first forming portion forming the back surface of the cover and a second forming portion forming the second surface of the transparent body. In the placement step, the conductive portion is placed on the second forming portion and the bus bar is placed on the first forming portion.