The present invention provides the hydrogenated product of a thermoplastic norbornene polymer excellent in characteristics as optical materials by reducing the residual amounts of the transition metal atoms originating from the polymerization catalyst used at the polymerization to 1 ppm or less of the hydrogenated product.Reduction of the residual amounts to below the desired level is attained by treating the reaction solution with the adsorbent during or after production of the hydrogenated product from the thermoplastic norbornene polymer.The hydrogenated product of the thermoplastic norbornene polymer thus obtained in which the residual amounts of the transition metal atoms are 1 ppm or less, has a wide utilization field, including a material for optical articles having excellent utilization characteristics such as substrates for optical elements, lenses and the like.