An absorber is capable of selective adsorption and removal of acidic gases of sulfur oxides, nitrogen oxides, chlorine compounds and sulfur-containing compounds such as hydrogen sulfide, as well as organic acid gases. The absorber is characterized by having a metal phthalocyanine supported on an ion exchanger, wherein the ion exchanger has a quarternary ammonium group as an ion-exchange group and the metal phthalocyanine contains iron phthalocyanine in an amount of 0.05-30 wt % of the ion exchanger.