Provided is a positive active material for a lithium secondary battery includes a lithium transition metal composite oxide having an α-NaFeO2-type crystal structure and represented by the composition formula of Li1+αMe1−αO2 (Me is a transition metal including Co, Ni and Mn and α>0). The positive active material contains Na in an amount of 900 ppm or more and 16000 ppm or less, or K in an amount of 1200 ppm or more and 18000 ppm or less.