In some embodiments, a non-volatile memory device includes a control logic circuit configured to generate a program signal and an erase signal based on control signals, a voltage generator configured to generate a program voltage and an erase voltage based on the program signal and the erase signal, a memory cell array including a memory cell, a string select transistor coupled to the memory cell, a bit-line coupled to the string select transistor, and a string select line coupled to the string select transistor, and a page buffer circuit coupled to the bit-line, and including a first precharge transistor that is configured to operate based on the program signal and the erase signal. The first precharge transistor is configured to apply the program voltage and the erase voltage to the bit-line in response to the program signal and the erase signal, respectively.