Method for producing functional polyester fiber, and polyester products using functional polyester fiber

Provided is a method for producing a functional polyester fiber that can be utilized in a broad range of areas, including lifestyle materials and industrial materials. By adding a reactive group to a polyester fiber and binding a crosslinking agent to the reactive group, functional agents can easily be bound to the polyester fiber. In addition, a polyester fiber with outstanding functional durability can be achieved without destroying the stability of the polyester fiber. The method for producing the functional polyester fiber involves: adding a hydroxyl group and/or a carboxyl group and/or an amino group to the polyester fiber as a reactive group; adding a crosslinking agent to the polyester fiber, to which the reactive group was added, that will react with the reaction group; and adding a functional agent that reacts with the crosslinking agent.