Disclosed are a polymer electrolyte membrane having both high ion conductivity and excellent chemical durability, a manufacturing method therefor, and an electrochemical device comprising same. The polymer electrolyte membrane of the present invention comprises an electrolyte composition, the electrolyte composition containing: an ion conductor; and a radical scavenger, wherein the radical scavenger comprises an organic cyclic compound having at least one functional group selected from the group consisting of a hydroxyl group (—OH), an amine group (—NH2), a carboxyl group (—COOH), and an amide group (—CONH2).