<p>A fused multi-filament fabrication (FmFF) method for the 3D printing of continuous carbon fiber-reinforced polymer (cCFRP) composites was proposed as an extension of the fused filament fabrication (FFF) method. The FmFF method enables the simultaneous deposition of multiple filaments using a single nozzle. The effect of simultaneous multi-filament deposition on the quality and mechanical properties of 3D-printed cCFRP composites was evaluated. Specifically, the FmFF process was investigated using a simultaneous five-filament deposition process, with the five filaments being integrated into a bundle and printed using a single nozzle. The quality differed depending on the path. In straight sections, the filament bundles were arranged in a regular pattern, whereas in curved sections, they were arranged unevenly owing to filament movement. The tensile and bending moduli of the cCFRP composites fabricated using the FmFF method (59 GPa and 50 GPa using <i>V</i>_f = 0.3 filaments) were almost identical to those obtained using the FFF method (60 GPa and 51 GPa). However, the bending strength was relatively low (FmFF: 451 MPa, FFF: 540 MPa), whereas the tensile strength was higher due to a larger curvature radius in the FmFF nozzle (FmFF: 1090 MPa, FFF: 800 MPa). Moreover, the bending failure mode was partial fragmentation and delamination, indicating relatively low interfacial adhesion between the layers. This study demonstrates the applicability of the FmFF method for high-throughput fabrication of lightweight small structural parts, while simultaneously identifying future challenges for improvement.</p>