An iodide compound is adsorbed and removed from an organic acid containing the iodide compound as an impurity by passing the organic acid through a packed bed of a cation-exchange resin having silver ion carried thereon at 50° C. or lower. The cation-exchange resin is a macroporous-type resin with an average particle size of 0.3 to 0.6 mm and an average pore size of 15 to 28 nm, and silver ion substitutes for 40 to 60% of the active site.