Fluoro-terminated hyperbranched poly(ether ketone)s (FHBPEKs) with controlled degrees of branching and their linear analogous poly(ether ketone) (LPEK) whose chemical structure and molecular weights were similar to those of FHBPEKs were synthesized and characterized. Depending on the amount of the core molecules, degrees of branching of 0.49 (FHBPEK), 0.62 (FHBPEK-CM01), and 0.67 (FHBPEK-CM02) could be obtained with little variation in the number-average molecular weights of the three FHBPEKs. From the dynamic mechanical analyses, it was investigated that the crossover of the storage modulus G'(omega) and the loss modulus G"(omega) started to disappear at a critical value (> 0.62-0.67) of the degree of branching, indicating a nearly Newtonian or little entanglement flow. The correlation time, tau(c), was determined from the shear relaxation moduli and the Cole-Davidson equation, which provided a unique means to evaluate the melt processability on the basis of the molecular mobility. Highly branched structure of FHBPEKs predominantly increased the molecular mobility and enhanced the melt processability, realizing the optimum processing temperature lowered by 52-72 degrees C depending on the degree of branching, compared to that of LPEK. Further insights into the correlation times with the Vogel-Tamman-Fulcher (VTF) equation and the Arrhenius equation provided some novel information about the temperature dependence of the molecular mobility and the activation energy, in conjunction with the processability and the fragility of the FHBPEKs in comparison to the LPEK.