Disclosed are a vertically-integrated 3-dimensional flash memory for improving a reliability of cells and a fabrication method thereof. The fabrication method of the vertically-integrated 3-dimensional flash memory includes sequentially stacking a first insulating layer and a second insulating layer on a substrate to form a plurality of insulating layers, etching a portion of the insulating layers to expose an area of the substrate, forming a channel layer on a side surface of the etched insulating layers and on the substrate, forming a first macaroni layer on the channel layer, and forming a second macaroni layer on the first macaroni layer such that a side surface and a lower surface of the second macaroni layer are surrounded by the first macaroni layer.