An object of the present invention is to provide an electrolyte membrane that suppresses swelling and shrinkage caused by water retained in the electrolyte membrane for a solid polymer-type fuel cell, improves the durability of the electrolyte membrane, and obtains excellent power generation characteristics with a low resistance. The electrolyte membrane for a solid polymer-type fuel cell includes, as a reinforcing membrane, a nonwoven fabric composed of an electrolyte material and PVDF bicomponent fibers 2a, thereby improving the durability of the electrolyte membrane. Furthermore, the bicomponent fiber 2a has pores 23 that can effectively retain generated water, thereby improving battery performance under the condition of a low humidity.