An electrolyte solution containing a compound (1) represented by the formula (1): wherein R1 and R2 are each independently a C1-C4 alkyl group optionally containing an ether bond; and a compound (11) represented by the formula (11): wherein R101 and R102 are each independently a substituent that is a C1-C7 alkyl group or the like. The substituent optionally contains one or more divalent to hexavalent hetero atoms in its structure, with one or more hydrogen atoms each optionally replaced by a fluorine atom or a C0-C7 functional group. Also disclosed is an electrochemical device containing the electrolyte solution, a lithium ion secondary battery containing the electrolyte solution, and a module including the electrochemical device or the lithium ion secondary battery.