A semiconductor memory device includes a memory block including a plurality of memory cells programmed to a plurality of program states during a program operation, a voltage generator to generate and apply a program voltage and a select line voltage to the memory block during the program operation, and a read and write circuit to temporarily store program data during the program operation and control a potential of bit lines of the memory block based on the temporarily stored program data. The voltage generator generates the select line voltage as a first select line voltage during a first program operation on some program states among the plurality of program states, or as a second select line voltage for which a potential is lower than a potential of the first select line voltage during a second program operation on remaining program states among the plurality of program states.