A fluorene-containing spiro-type conjugated polymer, poly(dipropargylfluorene), was synthesized via the cyclopolymerization of dipropargylfluorene by Mo- and W-based transition-metal catalysts. The polymerization of dipropargylfluorene proceeded well by MoCl5 catalyst itself to give a quantitative yield of polymer. The Mo-based catalysts are more effective than those of W-based catalysts. The structure of poly(dipropargylfluorene) was characterized by various instrumental methods (NMR, IR, and UV-visible spectroscopies) to have the conjugated polymer backbone carrying fluorene moieties. Analysis of the C-13 NMR spectrum revealed that the polymer structure consists of only six-membered rings. The resulting poly(dipropargylfluorene)s were brown or black powder and soluble in aromatics and halogenated hydrocarbons such as benzene, chlorobenzene, tetrahydrofuran, chloroform, and methylene chloride. Thermal and morphological properties of the polymer are also discussed.