A semiconductor memory device includes a memory cell array, a page buffer, and control logic. The memory cell array includes a plurality of memory cells for storing data. The page buffer is coupled to at least one memory cell among the plurality of memory cells through a bit line and is configured to store data in the at least one memory cell. The control logic is configured to control an operation of the page buffer. The page buffer includes a first transistor coupled between the bit line and a first node, a second transistor coupled between the bit line and an external power voltage terminal, and an internal operation circuit coupled to the first node.