Negative electrode active material and negative electrode for solid state battery including the same

A negative electrode active material for a solid state battery which comprises a core portion comprising a carbonaceous material and a shell portion at least partially coated on a surface of the core portion,

• wherein the carbonaceous material comprises a plurality of pores, which have a porosity of 5-30 vol %, and a pore size of 100-300 nm based on the largest diameter of the pores, and the carbonaceous material comprises at least one of primary particles or secondary particles formed by aggregation of the primary particles, and the primary particles have a diameter (D50) of 500 nm to 5 μm, and
• the shell portion comprises a metal oxide, and the metal oxide is at least one selected from the group consisting of iron oxides, titanium oxide, aluminum oxide, chromium trioxide, zinc oxide, copper oxides, magnesium oxide, zirconium dioxide, molybdenum trioxide, vanadium pentoxide, niobium pentoxide, iron oxide, manganese oxide, vanadium oxide, cobalt oxide, nickel oxide and tantalum pentoxide.