We have newly developed a high-pressure polymer NMR cell, which has a versatile use for both batchwise and on-line operations. The high-pressure cell withstands temperatures and pressures, at least, up to 373 K and 35 MPa, respectively. It was demonstrated that the sample solutions of not only viscous carbon tetrachloride but also non-viscous subcritical carbon dioxide smoothly flow in and out at moderate flow rates by measuring the flow rate dependence of the longitudinal relaxation times.