The purpose of the present invention is to provide a lithium ion secondary battery which has further improved service life characteristics. A lithium ion secondary battery according to the present invention is characterized by comprising: a positive electrode which contains a positive electrode active material that operates at 4.5 V or higher with respect to lithium; and an electrolyte solution which contains a cyclic sulfonic acid ester, LiN(FSO2)2, and an electrolyte solution solvent that contains a fluorinated ether.