NOVELTY - A positive electrode active material has active material (A) containing lithium-manganese-iron-phosphate (I) and active material (B) containing lithium-metal oxide (II). The active material (A) has average particle diameter of 8 mu m or less. The ratio of average particle diameter of active material (B) and average particle diameter of active material (A) is 1.5 or more.    USE - Positive electrode active material is used for nonaqueous electrolyte battery used for high-output electronic device and motor vehicle (all claimed), video camera, mobile telephone and notebook computer.    ADVANTAGE - The nonaqueous electrolyte battery containing the positive electrode active material has excellent cyclic characteristics and high discharge capacity, energy density and stability.    DETAILED DESCRIPTION - A positive electrode active material has active material (A) containing lithium-manganese-iron-phosphate of formula: LiaMnbFecAdPO4 (I), and active material (B) containing lithium-metal oxide of formula: LivMwM'xM"yOz (II). The active material (A) has average particle diameter of 8 mu m or less. The ratio of average particle diameter of active material (B) and average particle diameter of active material (A) is 1.5 or more.    a=0-2;    b+c+d=1 or less;    b,c,d,w,x,y=0-1;    A=magnesium, nickel, cobalt, aluminum, tungsten, niobium, titanium, silicon, chromium, copper or zinc;    v=more than 0 to less than 2;    w+x+y=1 or less;    z=more than 0 to less than 3;and    M,M',M"=nickel, cobalt, iron, manganese, copper, zinc, aluminum, chromium, vanadium, titanium, magnesium or zirconium.    INDEPENDENT CLAIMS are included for the following:    (1) nonaqueous electrolyte battery (1), which contains 15-70 weight% of active material (A) and 30-85 weight% of active material (B);    (2) high-output electronic device; and    (3) motor vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows schematic view of nonaqueous electrolyte secondary battery. (Drawing includes non-English language text)    Nonaqueous electrolyte battery (1)    Positive electrode (2)    Negative electrode (3)    Separator (4)    Gasket (7)