Memory device performing program operation and method of operating the same

A semiconductor memory device comprising:

• a memory block including a plurality of memory cells;
• a peripheral circuit configured to perform a program operation including a plurality of program loops on selected memory cells, among the plurality of memory cells;
• and
• a control logic, in a process of setting a voltage of a bit line connected to the selected memory cells during the program operation, configured to control the peripheral circuit to apply a program inhibit voltage to a bit line connected to first memory cells corresponding to a target program state of a first group determined by a number of current program loops, the first memory cells being not programmed to the target program state of the first group, apply the program inhibit voltage to a bit line connected to memory cells on which programming is determined to be completed in a previous program loop, among second memory cells corresponding to a target program state of a second group determined by the number of current program loops, and apply a program allowable voltage to a bit line connected to memory cells on which programming is determined to not be completed in the previous program loop, among the second memory cells corresponding to the target program state of the second group determined by the number of current program loops.