Provided are a manufacturing method of an optical fiber base material and an optical fiber base material manufactured in the manufacturing method, the manufacturing method including: a process of combining at least two core base materials 70 by fusion-bonding to produce a single core base material; a process of fusion-bonding a pair of dummy glass rods 61 and 62 at both ends of the core base material 70 to produce a starting glass rod; a process of depositing, at an outer surface of the starting glass rod, glass particles generated by flame hydrolysis, to produce a porous base material 80; and a process of sintering and vitrifying, into transparent glass, the porous base material 80, to produce an optical fiber base material 310 that includes a core portion and a clad portion.