[One] Mutual citations with related applications [2] This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0148838 filed on November 9, 2017, and all contents disclosed in the literature of the Korean patent application are incorporated as part of this specification. [3] [4] Technology field [5] The present invention relates to a negative electrode active material, a negative electrode comprising the negative electrode active material, and a secondary battery including the negative electrode, specifically, the negative electrode active material includes a carbonaceous matrix including first particles and second particles, and The first particles include a silicon core; An oxide layer disposed on the silicon core and including SiO x (0