Provided in a method of producing a plastic bottle in which molding cycle is improved and a highly transparent plastic bottle rarely having a problem of discoloration such as whitening is produced. The method according to the present invention is a method of producing a plastic bottle comprising 0.005 to 0.025 parts by mass of a 1,2-benzisothiazol-3(2H)-one 1,1-dioxide compound with respect to 100 parts by mass of a polyester resin, the method comprising preparing a masterbatch containing 0.01 to 0.5 parts by mass of the above-described 1,2-benzisothiazol-3(2H)-one 1,1-dioxide compound with respect to 100 parts by mass of the polyester resin, subsequently mixing the masterbatch and polyester resin to produce a mixture, and molding the mixture into the shape of a bottle. Further, it is preferred that the above-described polyester resin be a polyethylene terephthalate resin.