A fluoropolyether-containing compound of the following formula (1a): R.sup.aR.sup.2R.sup.1R.sup.b (1a) wherein the symbols are as defined in the specification. Also disclosed is a fluoropolyether-containing compound of the following formula (1b): R.sup.aR.sup.2R.sup.1R.sup.b (1b), as well as a method for producing a compound of the formula (A): FOCR.sup.2R.sup.1COOR.sup.12 (A) wherein the symbols are as defined in the specification.

Provided are an acidic gas removing agent with smaller variation in amounts of carbon dioxide absorption even in the coexistence of water in removing carbon dioxide in a gas, an acidic gas removing method, an absorption device provided with the acidic gas removing agent, and an acidic gas cleaning device. Used is an acidic gas removing agent containing one or more selected from the group consisting of a hydroxy group-containing compound and a derivative of the hydroxy group-containing compound each having a number-average molecular weight of less than 500, containing a constituent unit having 3 or more carbon atoms and one or more oxygen atoms, and having a solubility parameter (LogS) value of 2.25 or less.