A three-dimensional non-volatile memory device that may increase erase operation efficiency during an erase operation using Gate-Induced Drain Leakage (GIDL) current and a method for fabricating the three-dimensional non-volatile memory device. The non-volatile memory device includes a channel structure formed over a substrate including a plurality of inter-layer dielectric layers and a plurality of channel layers that are alternately stacked, and a first selection gate and a second selection gate that are disposed on a first side and a second side of the channel structure, wherein the first selection gate and the second selection gate are disposed on sidewalls of the multiple channel layers, respectively, wherein a work function of a material forming the first selection gate is different from a work function of a material forming the second selection gate.