<p>Red blood cells (RBCs) are subjected to intermittent deformation stress when they flow inside blood vessels throughout the body. We modeled such various deformation pattern using a microfluidic constriction channel mounted on an on-chip cell manipulation system, and measured viscoelastic responses of a RBC. Here we fabricated a microchannel with three narrow paths with different width, and observed shape recovery after the deformation through the paths under the feedback manipulation. Whereas the viscoelasticity of RBC is almost linear with respect to strain for a short loading time of tens of seconds, it becomes nonlinear for a long loading time of hundreds of seconds.</p>