The invention provides a fluorinated aromatic sulfonic acid catalyst in which sulfonic acid groups and aryl groups substituted by fluorine atoms or fluoroalkyl groups are bound to a matrix selected from the group consisting of polysiloxane and inorganic base material. This catalyst can be produced by introducing sulfonic acid groups and aryl groups substituted by fluorine atoms or fluoroalkyl groups into the above-described matrix. This catalyst is used in various acid-catalyzed reactions such as esterification, acylation, nitration, alkylation, etherification, etc., particularly acid-catalyzed reactions in the presence of water to show a high acid catalysis activity. In addition, since this catalyst is solid, its handling is so easy that recovery and reuse thereof is easy.