The purpose of the present invention is to provide: an electrolytic solution which enables the production of a secondary battery having excellent oxidation resistance and excellent storage stability at higher temperatures or the like; an electrochemical device such as a lithium ion secondary battery, in which the electrolytic solution is used; and a module in which the electrochemical device is used. The present invention is an electrolytic solution comprising a solvent and an electrolyte salt, said electrolytic solution being characterized in that the solvent comprises a fluorinated compound (A) represented by general formula (1) and a fluorinated compound (B) represented by general formula (2), wherein the content of the fluorinated compound (A) is 0.01 to 20 mass% in the solvent and the content of the fluorinated compound (B) is 10 to 80 mass% in the solvent. Rf1OCOOR (1) (wherein Rf1 represents a fluorinated alkyl group having 1 to 4 carbon atoms; and R represents a non-fluorinated alkyl group having 1 to 4 carbon atoms); and Rf2OCOORf3 (2) (wherein Rf2 and Rf3 are the same as or different from each other and independently represent a fluorinated alkyl group having 1 to 4 carbon atoms).