A purpose of one embodiment of the present invention is to provide a lithium ion secondary battery that has improved life-span characteristics. The first lithium ion secondary battery of the present invention comprises an electrolyte solution comprising a sulfone compound, a fluorinated ether compound and LiN(FSO2)2, and a negative electrode comprising a silicon material, wherein a content of LiN(FSO2)2 in the electrolyte solution is more than 5 weight % and 20 weight % or less.