Provided is a nonvolatile memory device which requires a lower initializing voltage such that the nonvolatile memory device can be operated at a low voltage. The nonvolatile memory device (10) includes: a first electrode layer (105) formed above a semiconductor substrate (100); a first oxygen-deficient tantalum oxide layer (106x) formed on the first electrode layer (105) and having a composition represented by TaOx where 0.8≦x≦1.9; a second oxygen-deficient tantalum oxide layer (106y) formed on the first oxygen-deficient tantalum oxide layer (106x) and having a composition represented by TaOy where 2.1≦y; and a second electrode layer (107) formed on the second tantalum oxide layer (106y). The second tantalum oxide layer (106y) has a pillar structure including a plurality of pillars.