To provide a method for manufacturing an optical fiber preform so as to improve dehydration of a soot preform.

In the process of dehydrating the soot preform 20 for an optical fiber by traversing the preform in a heating zone of a heating furnace 10, the soot preform 20 is traversed at least twice or more, and a waiting step is set between the traversing steps. In the waiting step, the soot preform 20 is temporarily stopped while the distance M between the position of the top end 21a of the start seed rod for the soot preform 20 and the position of the highest temperature part in the heating zone is controlled to satisfy M≤300 mm. Thus, the portion of the soot preform 20 which can be used as the optical fiber including the upper end neighborhood can be sufficiently dehydrated.