A semiconductor memory device and an erase method in the same are disclosed. The semiconductor memory device includes a memory cell array configured to have a cell string in which memory cells are coupled, a block switch configured to switch a global word line and a word line of the memory cell array, a block decoder configured to control the block switch, and a recycle switch configured to use an erase voltage charged in a P-well of the memory cell array as a supply voltage of the block decoder.