To provide a polyester based powder coating resin which excels in the adhesion to an article to be coated and does not contain a heavy metal in consideration of environmental pollution and a polyester based powder coating using the same.

The polyester based powder coating resin mainly comprises an aromatic dicarboxylic acid and a glycol, has an acid value of 15-65 mg KOH/g, and comprises 100-400 ppm magnesium compound having a coated layer composed of titanic acid. A method for manufacturing a polyester based powder coating resin comprises using a magnesium compound having a coated layer composed of titanic acid as a polymerization catalyst and adding the above compound in an amount of 100-400 ppm to the resin to be obtained. The polyester based powder coating contains the above resin.