It is an object of the present invention to provide a positive electrode material having a large ratio of the discharge capacity around 4 V to the total discharge capacity including the discharge capacity at 4V or lower while making the discharge capacity around 4 V sufficient, for the purpose of providing a lithium secondary battery using a lithium transition metal phosphate compound excellent in thermal stability, utilizing the discharge potential around 4V (vs. Li/Li+) that is higher than the discharge potential of LiFePO4, and being advantageous with respect to the detection of the end of discharge state, and a lithium secondary battery using the same. The present invention uses a positive active material for a lithium secondary battery containing a lithium transition metal phosphate compound represented by LiMn1-x-yFexCoyPO4(0.1≦x≦0.2, 0