Dynamic viscoelasticity and birefringence of two poly(1-butyl-3-vinylimidazolium) based polymerized ionic liquids, PC4VICPFSI and PC(4)VINfO, are investigated by using hand-made shear and tensile rheo-optical apparatus for a further consideration of sub-Rouse mode in polymerized ionic liquids systems. Sub-Rouse mode spectrum for PC4VICPFSI whose counter anions is the same chemical structure as TFSI- and different shape showed the same component function as sub-Rouse mode for PC4VITFSI. On the other hand, sub-Rouse mode spectrum for PC(4)VINfO whose counter anions is the same ionic size as TFSI- but different chemical structure became sharper than that of PC4VITFSI. This result indicated that plasticization effect of counter anions would be more responsible for sub-Rouse mode.