An object of the present invention is to provide an optical fiber manufacturing method and an optical fiber in which an increase in the transmission loss is suppressed by preventing hydroxyl group from entering near the core portion. This invention provides a method for manufacturing an optical fiber 10 including forming a glass pipe 16 by applying a ring portion 15 on the inner face of a starting pipe 14 as a starting material, inserting a glass rod 13 that becomes a central core portion 11 and a depressed portion 12 into the inside of the glass pipe 16, integrating the glass pipe 16 and the glass rod 13 by collapse to form a glass body 17, forming a preform 10a by providing a jacket portion 18 outside the glass body 17, and drawing the preform 10a, wherein the thickness of the starting pipe 14 is set in a range from 4 mm to 8 mm.