The invention provides a fluoroethercarboxylic acid which is represented by the general formula (I): Rf.sup.1OCHFCF.sub.2ORf.sup.2COOM (I) wherein Rf.sup.1 represents a partially or fully fluorinated alkyl group, which may optionally be interrupted with one or more oxygen atoms, Rf.sup.2 represents a partially or fully fluorinated alkylene group, which may optionally be interrupted with one or more oxygen atoms, and M represents a monovalent alkali metal, NH.sub.4 or H. The fluoroethercarboxylic acid can be suitably used as a surfactant and is low in bioaccumulation. The invention is also a method of fluoropolymer production and an aqueous fluoropolymer dispersion, using the fluoroethercarboxylic acid as a surfactant.