A non-volatile semiconductor memory device includes a semiconductor layer of a first conductivity type, and a plurality of wells of a second conductivity type formed on the first semiconductor layer, the wells being arranged in a first direction. A memory block is arranged in each well. A plurality of word lines are provided, each word line being commonly connected to a plurality of NAND cell units in one memory block. A plurality of bit lines extend in a first direction, the bit lines being connected to first ends of the NAND cell units present in the memory blocks. A source line is connected to second ends of the NAND cell units. A well driver performs a control of selectively providing a first voltage or a second voltage higher than the first voltage to each well.