A non-aqueous electrolyte secondary battery includes a positive electrode (1) containing lithium cobalt oxide as a positive electrode active material, a negative electrode (2) containing molybdenum dioxide as a negative electrode active material, and a non-aqueous electrolyte. The mass ratio of the negative electrode active material to the positive electrode active material is within the range of from 0.725 to 0.480. The conductive agent of the negative electrode consists of a carbon material having a lattice constant C.sub.0 along a stacking direction of from 6.7 .ANG. to 6.8 .ANG., as determined by X-ray diffraction, or the negative electrode contains no conductive agent made of carbon material.