Optical fiber preform equipment is used for prefabrication equipment in the early stage of optical fiber production, and only a few in China can produce it. An optical fiber preform manufacturing apparatus that can simultaneously mount and manufacture a plurality of preforms and can be adjusted according to the length of the preforms is provided. The apparatus uses at least one burner to heat a plurality of quartz tubes to deposit chemical reactants on the outer wall of the quartz tubes. Finally, the apparatus comprises a longitudinally extending chamber housing, and a variable length structure mounted inside the chamber housing in the longitudinal direction, wherein the variable length structure is adjustable according to the length of the quartz tube and reciprocates in the longitudinal direction.