An optical fiber preform comprises a central core portion having a maximal
value Nc of refractive index in the center, and outside the central core
portion, comprising at least a depressed portion having a minimal value
Nd of refractive index, a ring portion having a maximal value Nr of
refractive index and an outside cladding layer having a maximal value No
of refractive index. The optical fiber preform satisfies a relation of
Nc.gtoreq.Nr>No>Nd among the values of refractive index. A method
of the optical fiber preform comprises fabricating a glass rod by
inserting a rod containing at least the central core portion into a pipe
containing at least the depressed portion and integrating them,
fabricating a glass pipe having the ring portion, and fabricating a
vitreous body by integrating the glass rod and the glass pipe by
collapsing after inserting the glass rod into the glass pipe.