Provided is a local self-boosting method of a flash memory device including at least one string having memory cells respectively connected to wordlines. The local self-boosting method includes forming a potential well at a channel of the string and forming potential walls at the potential well to be disposed at both sides of a channel of a selected one of the memory cells. The channel of the selected memory cell is locally limited by the potential walls and boosted when a program voltage is applied to the selected memory cell.