A nonaqueous electrolyte includes: a solvent, an electrolyte salt, and at least one of heteropolyacid salt compounds represented by the following formulae (I) and (II): HxAy[BD12O40].zH2O (I), HpAq[B5D30O110].rH2O (II). A represents Li, Na, K, Rb, Cs, Mg, Ca, Al, NH4, or an ammonium salt or phosphonium salt; B represents P, Si, As or Ge; D represents at least one element selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Tc, Rh, Cd, In, Sn, Ta, W, Re and Tl; x, y and z are values falling within the ranges of (0≦x≦1), (2≦y≦4) and (0≦z≦5), respectively; and p, q and r are values falling within the ranges of (0≦p≦5), (10≦q≦15) and (0≦r≦15), respectively.