Disclosed is a polyester sewing thread usable for a fabric for an airbag and a cushion for an airbag. A polyester sewing thread is obtained by doubling and twisting a specific polyester yarn including a plurality of polyester filaments, and bonding the polyester yarn in the manner of in-bonding, out-bonding, or in-and-out bonding. The polyester fiber has high strength, middle elongation, and dry heat shrinkage, and may be used as sewing threads with excellent physical properties similar to those of a sewing thread of existing polyamide fiber (Nylon 66). A method for producing the thread is also disclosed.