Disclosed are an adsorption process whereby a fluorocarboxylic acid having an ether bond can be adsorbed to a high extent by using active carbon without changing the form thereof, and a desorption process whereby the adsorbed material can be desorbed from the active carbon to thereby enable the reuse of the active carbon and the adsorbed material. In the aforesaid processes, a solution containing a fluorocarboxylic acid having an ether bond is contacted with active carbon and thus the active carbon is allowed to adsorb the fluorocarboxylic acid, to thereby give a solution having a small fluorocarboxylic acid content. Then, the active carbon having adsorbed the fluorocarboxylic acid is heated to thereby desorbs the fluorocarboxylic acid from the active carbon.