Dynamic microfluidic gelation enables the fabrication of bundle‐structured multiple parallel microgel filaments from an aqueous two‐phase system. The formation mechanism of shear‐induced filaments from an alginate (Alg)/polyvinyl alcohol (PVA) blend is studied using red‐colored PVA and a titanium alkoxide PVA crosslinker. Bundle‐structured Alg microgel filaments are formed through contact with a Ca2+ crosslinker. In this process, the PVA acts as a sacrificial polymer to maintain the Alg gel filaments because approximately 90% of the red‐colored PVA is released from the Ca2+‐crosslinked Alg gel filaments into the wash water. In addition, the fabrication of PVA gel filaments shows that the sacrificial PVA is also transformed into fibrillar domains under shear. However, the filament structure cannot be formed from a single‐phase PVA/Alg solution. These results clearly show that the bundle‐structured gel filaments are maintained by preventing the fusion of filaments during gelation based on the tendency of the non‐crosslinked filaments to cause splitting of the gelled filaments.