The present disclosure relates to a polyarylene ether-based polymer for an electrolyte membrane of a fuel cell, represented by the following Chemical Formula 1. When the polyarylene ether-based polymer for an electrolyte membrane of a fuel cell is applied to the manufacture of a membrane-electrode assembly through a decal process, the hot pressing temperature may be controlled to about 120° C. so as to conform to a low glass transition temperature. Therefore, it is possible to solve the problems of deterioration of an electrolyte membrane or incomplete transfer of an electrode catalyst layer, caused by the high hot pressing temperature applied in the case of the conventional hydrocarbon-based polymer material.