A lithium metal electrode includes a current collector having a surface irregularity structure, a lithium metal layer disposed outside of the surface irregularity structure except the uppermost surface of the surface irregularity structure in the current collector, an electron-insulating protective layer disposed outside of the lithium metal layer, and a lithium ion-isolating layer disposed (1) on the uppermost surface of the surface irregularity structure of the current collector, or (2) on the uppermost surface of the surface irregularity structure of the current collector, on the uppermost surface of the lithium metal layer, and on the uppermost surface of the electron-insulating protective layer, wherein the electron-insulating protective layer includes a non-porous layer transporting lithium ions and having no pores, and a polymer porous layer disposed outside thereof. A lithium secondary battery and flexible secondary battery including the lithium metal electrode are also provided.