Polyvinyl alcohol fibers that exhibit excellent heat aging resistance when used for a long time under high temperature conditions are provided. The polyvinyl alcohol fibers contain: an antioxidant composed of inorganic or organic water soluble salt of at least one metal selected from the group consisting of manganese, copper, iron, nickel, cobalt, and zinc; and a boron compound that acts as a chelating agent for the antioxidant, wherein the content of the antioxidant in the fiber is 0.05 % by mass or more, and a proportion (mass ratio in %) of the boron compound to the antioxidant is 0.5% or more.