An active material comprises a core particle containing LiCo(1−x)MxO2 and/or Li(Mn(1−y)My)2O4, and a coating part covering at least part of a surface of the core particle, while the coating part contains LiVOPO4. Here, M is at least one element selected from the group consisting of Al, Mg, and transition elements, 0.95≧x≧0, 0.2≧y≧0, and V in LiVOPO4 may partly be substituted by at least one element selected from the group consisting of Ti, Ni, Co, Mn, Fe, Zr, Cu, Zn, and Yb.