To provide a flame-retardant polyester resin composition substantially free from a halogen, and capable of easily achieving a V-2 level of UL-94 standard, sometimes a V-0 level under a favorable condition, and having excellent hydrolysis resistance.

The flame-retardant polyester composition comprises (A) 100 pts. wt. resin component (A-component) containing at least 60 wt.% aromatic polyester resin, (B) 1-100 pts. wt. organophosphorus compound (B-component) {suitable example: 2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane-3,9-di-α-methylbenzyl-3,9-dioxide compound}, (C) 0.1-100 pts. wt. inorganic salt (C-component) of at least one kind selected from the group consisting of an alkali metal salt and an alkaline earth metal salt, (D) 0-50 pts. wt. flame retardance-improving resin (D-component) and (E) 0-200 pts. wt. filler (E-component). The molded product comprises the composition.